Common mode noise mitigation for integrated touch screens

ABSTRACT

Some touch screens can be formed by at least partially integrating touch sensing circuitry into a display pixel stackup. In some examples, noise can be introduced into touch sensor panel measurements, for example, from display data lines of a display device proximate to the touch sensor panel. In some examples, rows or columns of touch electrodes can be split and a first portion of the touch sensor panel can be stimulated to measure capacitance and noise and a second portion of the touch sensor panel can be unstimulated and measure noise. In some examples, both the first and the second portions of the touch sensor panel can be stimulated using orthogonal stimulation codes. In some examples, measurements from the first and/or second portions of the touch sensor panel can be subtracted from measurements from the other portion of the touch sensor panel to eliminate or reduce common mode noise.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/551,691, filed on Aug. 26, 2019, published on Apr. 2, 2020 as U.S.Publication No. 2020-0103993, and claims benefit of U.S. ProvisionalPatent Application No. 62/738,935, filed Sep. 28, 2018, the entiredisclosures of which are hereby incorporated by reference for allpurposes.

FIELD OF THE DISCLOSURE

This relates generally to devices including a sensor panel and, morespecifically, to touch-sensitive devices configured to reduce noiselevels.

BACKGROUND OF THE DISCLOSURE

Many types of input devices are presently available for performingoperations in a computing system, such as buttons or keys, mice,trackballs, joysticks, touch sensor panels, touch screens and the like.Touch screens, in particular, are popular because of their ease andversatility of operation as well as their declining price. Touch screenscan include a touch sensor panel, which can be a clear panel with atouch-sensitive surface, and a display device such as a liquid crystaldisplay (LCD), light emitting diode (LED) display or organic lightemitting diode (OLED) display that can be positioned partially or fullybehind the panel so that the touch-sensitive surface can cover at leasta portion of the viewable area of the display device. Touch screens canallow a user to perform various functions by touching the touch sensorpanel using a finger, stylus or other object at a location oftendictated by a user interface (UI) being displayed by the display device.In general, touch screens can recognize a touch and the position of thetouch on the touch sensor panel, and the computing system can theninterpret the touch in accordance with the display appearing at the timeof the touch, and thereafter can perform one or more actions based onthe touch. In the case of some touch sensing systems, a physical touchon the display is not needed to detect a touch. For example, in somecapacitive-type touch sensing systems, fringing electric fields used todetect touch can extend beyond the surface of the display, and objectsapproaching near the surface may be detected near the surface withoutactually touching the surface.

Capacitive touch sensor panels can be formed by a matrix of partially orfully transparent or non-transparent conductive plates (e.g., touchelectrodes or sensing electrodes) made of materials such as Indium TinOxide (ITO). In some examples, the conductive plates can be formed fromother materials including conductive polymers, metal mesh, graphene,nanowires (e.g., silver nanowires) or nanotubes (e.g., carbonnanotubes). It is due in part to their substantial transparency thatsome capacitive touch sensor panels can be overlaid on a display to forma touch screen, as described above. Some touch screens can be formed byat least partially integrating touch sensing circuitry into a displaypixel stackup (i.e., the stacked material layers forming the displaypixels).

In some cases, the proximity between a capacitive touch sensor panelsand the display can allow for noise from the display circuitry todegrade the performance of the capacitive touch sensor panel. The amountof noise interference can increase as the distance between thecapacitive touch sensor panel and the display decreases.

SUMMARY OF THE DISCLOSURE

This relates to reducing noise in touch sensor panel measurements. Noisecan be introduced into touch sensor panel measurements, for example,from display data lines (e.g., display electrodes) of a display deviceproximate to the touch sensor panel (e.g., in a touch screen). In someexamples, rows or columns of touch electrodes can be split such that afirst portion of the touch sensor panel can be stimulated to measurechanges in capacitance and noise and a second portion of the touchsensor panel can be unstimulated and measure noise. The noise measuredby the second portion can be subtracted from the measurements from thefirst portion to eliminate or reduce the common mode noise in themeasurements from the first portion. A similar measurement scheme can berepeated to obtain measurements from the second portion eliminating orreducing common mode noise (e.g., stimulating the second portion tomeasure changes in capacitance and measuring noise from the unstimulatedfirst portion). In some examples, both the first and the second portionsof the touch sensor panel can be stimulated using orthogonal stimulationcodes to measure changes in capacitance for the touch sensor panel fromwhich common mode noise can be eliminated or reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1E illustrate example systems that can implement touch sensingand common mode noise correction according to examples of thedisclosure.

FIG. 2 illustrates a block diagram of an example computing system thatcan implement touch sensing and common mode noise correction accordingto examples of the disclosure.

FIG. 3 illustrates an example touch screen including touch sensingcircuitry configured as drive and sense regions or lines according toexamples of the disclosure.

FIG. 4 illustrates an example touch screen including touch sensingcircuitry configured as pixelated electrodes according to examples ofthe disclosure.

FIG. 5 illustrates an example mutual capacitance scan of an examplerow-column touch sensor panel.

FIGS. 6A-6D illustrate portions of example touch screens according toexamples of the disclosure.

FIGS. 7A-7E illustrate example sense circuits to eliminate or reducecommon mode noise according to examples of the disclosure.

FIG. 8 illustrates an example process to eliminate or reduce common modenoise according to examples of the disclosure.

FIG. 9 illustrates an example stackup of a touch screen according toexamples of this disclosure.

DETAILED DESCRIPTION

In the following description of examples, reference is made to theaccompanying drawings which form a part hereof, and in which it is shownby way of illustration specific examples that can be practiced. It is tobe understood that other examples can be used and structural changes canbe made without departing from the scope of the disclosed examples.

This relates to reducing noise in touch sensor panel measurements. Noisecan be introduced into touch sensor panel measurements, for example,from display data lines (e.g., display electrodes) of a display deviceproximate to with the touch sensor panel (e.g., in a touch screen). Insome examples, rows or columns of touch electrodes can be split suchthat a first portion of the touch sensor panel can be stimulated tomeasure changes in capacitance and noise and a second portion of thetouch sensor panel can be unstimulated and measure noise. The noisemeasured by the second portion can be subtracted from the measurementsfrom the first portion to eliminate or reduce the common mode noise inthe measurements from the first portion. A similar measurement schemecan be repeated to obtain measurements from the second portioneliminating or reducing common mode noise (e.g., stimulating the secondportion to measure changes in capacitance and measuring noise from theunstimulated first portion). In some examples, both the first and thesecond portions of the touch sensor panel can be stimulated usingorthogonal stimulation codes to measure changes in capacitance for thetouch sensor panel from which common mode noise can be eliminated orreduced.

FIGS. 1A-1E illustrate example systems that can implement touch sensingand common mode noise correction according to examples of thedisclosure. FIG. 1A illustrates an example mobile telephone 136 thatincludes a touch screen 124 and a computing system that can implementcommon mode noise correction according to examples of the disclosure.FIG. 1B illustrates an example digital media player 140 that includes atouch screen 126 and a computing system that can implement common modenoise correction according to examples of the disclosure. FIG. 1Cillustrates an example personal computer 144 that includes a touchscreen 128 and a computing system that can implement common mode noisecorrection according to examples of the disclosure. FIG. 1D illustratesan example tablet computing device 148 that includes a touch screen 130and a computing system that can implement common mode noise correctionaccording to examples of the disclosure. FIG. 1E illustrates an examplewearable device 150 that includes touch screen 152 and a computingsystem and can be attached to a user using a strap 154 and that canimplement common mode noise correction according to examples of thedisclosure. The touch screen and computing system that can implementtouch sensing and common mode noise correction can be implemented inother devices.

Touch screens 124, 126, 128, 130 and 150 can be based on, for example,self-capacitance or mutual capacitance sensing technology, or anothertouch sensing technology. For example, a self-capacitance based touchsystem can include a matrix of small, individual plates of conductivematerial that can be referred to as touch node electrodes (as describedbelow with reference to touch screen 420 in FIG. 4). For example, atouch screen can include a plurality of individual touch nodeelectrodes, each touch node electrode identifying or representing aunique location on the touch screen at which touch or proximity (i.e., atouch or proximity event) is to be sensed, and each touch node electrodebeing electrically isolated from the other touch node electrodes in thetouch screen/panel. Such a touch screen can be referred to as apixelated self-capacitance touch screen, though it is understood that insome examples, the touch node electrodes on the touch screen can be usedto perform scans other than self-capacitance scans on the touch screen(e.g., mutual capacitance scans). During operation, a touch nodeelectrode can be stimulated with an AC waveform, and theself-capacitance to ground of the touch node electrode can be measured.As an object approaches the touch node electrode, the self-capacitanceto ground of the touch node electrode can change (e.g., increase). Thischange in the self-capacitance of the touch node electrode can bedetected and measured by the touch sensing system to determine thepositions of multiple objects when they touch, or come in proximity to,the touch screen. In some examples, the electrodes of a self-capacitancebased touch system can be formed from rows and columns of conductivematerial (as described below with reference to touch screen 320 in FIG.3), and changes in the self-capacitance to ground of the rows andcolumns can be detected, similar to above. In some examples, a touchscreen can be multi-touch, single touch, projection scan, full-imagingmulti-touch, capacitive touch, etc.

In some examples, touch screens 124, 126, 128, 130 and 150 can be basedon mutual capacitance. A mutual capacitance based touch system caninclude drive and sense lines that may cross over each other ondifferent layers, or may be adjacent to each other on the same layer(e.g., as illustrated in touch screen 320 in FIG. 3). The crossing oradjacent locations can be referred to as touch nodes. During operation,the drive line can be stimulated with an AC waveform and the mutualcapacitance of the touch node can be measured. As an object approachesthe touch node, the mutual capacitance of the touch node can change(e.g., decrease). This change in the mutual capacitance of the touchnode can be detected and measured by the touch sensing system todetermine the positions of multiple objects when they touch, or come inproximity to, the touch screen. In some examples, the electrodes of amutual-capacitance based touch system can be formed from a matrix ofsmall, individual plates of conductive material, and changes in themutual capacitance between plates of conductive material can bedetected, similar to above.

In some examples, touch screens 124, 126, 128, 130 and 150 can be basedon mutual capacitance and/or self-capacitance. The electrodes can bearrange as a matrix of small, individual plates of conductive material(e.g., as in touch screen 420 in FIG. 4) or as drive lines and senselines (e.g., as in touch screen 320 in FIG. 3), or in another pattern.The electrodes can be configurable for mutual capacitance orself-capacitance sensing or a combination of mutual and self-capacitancesensing. For example, in one mode of operation electrodes can beconfigured to sense mutual capacitance between electrodes and in adifferent mode of operation electrodes can be configured to senseself-capacitance of electrodes. In some examples, some of the electrodescan be configured to sense mutual capacitance therebetween and some ofthe electrodes can be configured to sense self-capacitance thereof.

FIG. 2 illustrates a block diagram of an example computing system thatcan implement touch sensing and common mode noise correction accordingto examples of the disclosure. Computing system 200 could be includedin, for example, mobile telephone 136, digital media player 140,personal computer 144, tablet computing device 148, wearable device 150,or any mobile or non-mobile computing device that includes a touchscreen. Computing system 200 can include an integrated touch screen 220to display images and to detect touch and/or proximity (e.g., hover)events from an object (e.g., finger 203 or active or passive stylus 205)at or proximate to the surface of the touch screen 220. Computing system200 can also include an application specific integrated circuit (“ASIC”)illustrated as touch ASIC 201 to perform touch and/or stylus sensingoperations. Touch ASIC 201 can include one or more touch processors 202,peripherals 204, and touch controller 206. Touch ASIC 201 can be coupledto touch sensing circuitry of touch screen 220 to perform touch and/orstylus sensing operations (described in more detail below). Peripherals204 can include, but are not limited to, random access memory (RAM) orother types of memory or storage, watchdog timers and the like. Touchcontroller 206 can include, but is not limited to, one or more sensechannels in receive circuitry 208, panel scan engine 210 (which caninclude channel scan logic) and transmit circuitry 214 (which caninclude analog or digital driver logic). In some examples, the transmitcircuitry 214 and receive circuitry 208 can be reconfigurable by thepanel scan engine 210 based the scan event to be executed (e.g., mutualcapacitance row-column scan, mutual capacitance row-row scan,differential mutual capacitance scan, mutual capacitance column-columnscan, row self-capacitance scan, column self-capacitance scan, touchspectral analysis scan, stylus spectral analysis scan, stylus scan,etc.). Panel scan engine 210 can access RAM 212, autonomously read datafrom the sense channels and provide control for the sense channels(e.g., described in more detail with respect to sense channel 780 inFIG. 7E). The touch controller 206 can also include a scan plan (e.g.,stored in RAM 212) which can define a sequence of scan events to beperformed at the touch screen. The scan plan can include informationnecessary for configuring or reconfiguring the transmit circuitry andreceive circuitry for the specific scan event to be performed. Results(e.g., touch signals or touch data) from the various scans can also bestored in RAM 212. In addition, panel scan engine 210 can providecontrol for transmit circuitry 214 to generate stimulation signals atvarious frequencies and/or phases that can be selectively applied todrive regions of the touch sensing circuitry of touch screen 220. Touchcontroller 206 can also include a spectral analyzer to determine lownoise frequencies for touch and stylus scanning. The spectral analyzercan perform spectral analysis on the scan results from an unstimulatedtouch screen. Although illustrated in FIG. 2 as a single ASIC, thevarious components and/or functionality of the touch ASIC 201 can beimplemented with multiple circuits, elements, chips, and/or discretecomponents.

Computing system 200 can also include an application specific integratedcircuit illustrated as display ASIC 216 to perform display operations.Display ASIC 216 can include hardware to process one or more stillimages and/or one or more video sequences for display on touch screen220. Display ASIC 216 can be configured to generate read memoryoperations to read the data representing the frame/video sequence from amemory (not shown) through a memory controller (not shown), for example.Display ASIC 216 can be configured to perform various processing on theimage data (e.g., still images, video sequences, etc.). In someexamples, display ASIC 216 can be configured to scale still images andto dither, scale and/or perform color space conversion on the frames ofa video sequence. Display ASIC 216 can be configured to blend the stillimage frames and the video sequence frames to produce output frames fordisplay. Display ASIC 216 can also be more generally referred to as adisplay controller, display pipe, display control unit, or displaypipeline. The display control unit can be generally any hardware and/orfirmware configured to prepare a frame for display from one or moresources (e.g., still images and/or video sequences). More particularly,display ASIC 216 can be configured to retrieve source frames from one ormore source buffers stored in memory, composite frames from the sourcebuffers, and display the resulting frames on touch screen 220.Accordingly, display ASIC 216 can be configured to read one or moresource buffers and composite the image data to generate the outputframe.

Display ASIC 216 can provide various control and data signals to thedisplay, including timing signals (e.g., one or more clock signals)and/or vertical blanking period and horizontal blanking intervalcontrols. The timing signals can include a pixel clock that can indicatetransmission of a pixel. The data signals can include color signals(e.g., red, green, blue). The display ASIC 216 can control the touchscreen 220 in real-time, providing the data indicating the pixels to bedisplayed as the touch screen is displaying the image indicated by theframe. The interface to such a touch screen 220 can be, for example, avideo graphics array (VGA) interface, a high definition multimediainterface (HDMI), a digital video interface (DVI), a LCD interface, anLED display interface, an OLED display interface, a plasma interface, orany other suitable interface.

In some examples, a handoff module 218 can also be included in computingsystem 200. Handoff module 218 can be coupled to the touch ASIC 201,display ASIC 216, and touch screen 220, and can be configured tointerface the touch ASIC 201 and display ASIC 216 with touch screen 220.The handoff module 218 can appropriately operate the touch screen 220according to the scanning/sensing and display instructions from thetouch ASIC 201 and the display ASIC 216. In other examples, the displayASIC 216 can be coupled to display circuitry of touch screen 220 andtouch ASIC 201 can be coupled to touch sensing circuitry of touch screen220 without handoff module 218.

Touch screen 220 can use liquid crystal display (LCD) technology, lightemitting polymer display (LPD) technology, light emitting diode (LED)technology, organic LED (OLED) technology, or organic electroluminescence (OEL) technology, although other display technologies canbe used in other examples. In some examples, the touch sensing circuitryand display circuitry of touch screen 220 can be stacked on top of oneanother. For example, a touch sensor panel can cover some or all of asurface of the display (e.g., fabricated one on top of the next in asingle stack-up or formed from adhering together a touch sensor panelstack-up with a display stack-up). In other examples, the touch sensingcircuitry and display circuitry of touch screen 220 can be partially orwholly integrated with one another. The integration can be structuraland/or functional. For example, some or all of the touch sensingcircuitry can be structurally in between the substrate layers of thedisplay (e.g., between two substrates of a display pixel cell). Portionsof the touch sensing circuitry formed outside of the display pixel cellcan be referred to as “on-cell” portions or layers, whereas portions ofthe touch sensing circuitry formed inside of the display pixel cell canbe referred to as “in cell” portions or layers. Additionally, someelectronic components can be shared, and used at times as touch sensingcircuitry and at other times as display circuitry. For example, in someexamples, common electrodes can be used for display functions duringactive display refresh and can be used to perform touch sensingfunctions during touch sensing periods. A touch screen stack-up sharingcomponents between sensing functions and display functions can bereferred to as an in-cell touch screen.

Computing system 200 can also include a host processor 228 coupled tothe touch ASIC 201, and can receive outputs from touch ASIC 201 (e.g.,from touch processor 202 via a communication bus, such as an serialperipheral interface (SPI) bus, for example) and perform actions basedon the outputs. Host processor 228 can also be connected to programstorage 232 and display ASIC 216. Host processor 228 can, for example,communicate with display ASIC 216 to generate an image on touch screen220, such as an image of a user interface (UI), and can use touch ASIC201 (including touch processor 202 and touch controller 206) to detect atouch on or near touch screen 220, such as a touch input to thedisplayed UI. The touch input can be used by computer programs stored inprogram storage 232 to perform actions that can include, but are notlimited to, moving an object such as a cursor or pointer, scrolling orpanning, adjusting control settings, opening a file or document, viewinga menu, making a selection, executing instructions, operating aperipheral device connected to the host device, answering a telephonecall, placing a telephone call, terminating a telephone call, changingthe volume or audio settings, storing information related to telephonecommunications such as addresses, frequently dialed numbers, receivedcalls, missed calls, logging onto a computer or a computer network,permitting authorized individuals access to restricted areas of thecomputer or computer network, loading a user profile associated with auser's preferred arrangement of the computer desktop, permitting accessto web content, launching a particular program, encrypting or decoding amessage, and/or the like. Host processor 228 can also perform additionalfunctions that may not be related to touch processing.

Computing system 200 can include one or more processors, which canexecute software or firmware implementing various functions.Specifically, for integrated touch screens which share componentsbetween touch and/or stylus sensing and display functions, the touchASIC and display ASIC can be synchronized so as to properly share thecircuitry of the touch sensor panel. The one or more processors caninclude one or more of the one or more touch processors 202, a processorin display ASIC 216, and/or host processor 228. In some examples, thedisplay ASIC 216 and host processor 228 can be integrated into a singleASIC, though in other examples, the host processor 228 and display ASIC216 can be separate circuits coupled together. In some examples, hostprocessor 228 can act as a master circuit and can generatesynchronization signals that can be used by one or more of the displayASIC 216, touch ASIC 201 and handoff module 218 to properly performsensing and display functions for an in-cell touch screen. Thesynchronization signals can be communicated directly from the hostprocessor 228 to one or more of the display ASIC 216, touch ASIC 201 andhandoff module 218. Alternatively, the synchronization signals can becommunicated indirectly (e.g., touch ASIC 201 or handoff module 218 canreceive the synchronization signals via the display ASIC 216).

Computing system 200 can also include a wireless module (not shown). Thewireless module can implement a wireless communication standard such asa WiFi®, BLUETOOTH™ or the like. The wireless module can be coupled tothe touch ASIC 201 and/or host processor 228. The touch ASIC 201 and/orhost processor 228 can, for example, transmit scan plan information,timing information, and/or frequency information to the wireless moduleto enable the wireless module to transmit the information to an activestylus, for example (i.e., a stylus capable generating and injecting astimulation signal into a touch sensor panel). For example, thecomputing system 200 can transmit frequency information indicative ofone or more low noise frequencies the stylus can use to generate astimulation signals. Additionally or alternatively, timing informationcan be used to synchronize the stylus 205 with the computing system 200,and the scan plan information can be used to indicate to the stylus 205when the computing system 200 performs a stylus scan and expects stylusstimulation signals (e.g., to save power by generating a stimulus onlyduring a stylus scan period). In some examples, the wireless module canalso receive information from peripheral devices, such as an activestylus 205, which can be transmitted to the touch ASIC 201 and/or hostprocessor 228. In other examples, the wireless communicationfunctionality can be incorporated in other components of computingsystem 200, rather than in a dedicated chip.

Note that one or more of the functions described herein can be performedby firmware stored in memory and executed by the touch processor intouch ASIC 201, or stored in program storage and executed by hostprocessor 228. The firmware can also be stored and/or transported withinany non-transitory computer-readable storage medium for use by or inconnection with an instruction execution system, apparatus, or device,such as a computer-based system, processor-containing system, or othersystem that can fetch the instructions from the instruction executionsystem, apparatus, or device and execute the instructions. In thecontext of this document, a “non-transitory computer-readable storagemedium” can be any medium (excluding a signal) that can contain or storethe program for use by or in connection with the instruction executionsystem, apparatus, or device. The non-transitory computer readablemedium storage can include, but is not limited to, an electronic,magnetic, optical, electromagnetic, infrared, or semiconductor system,apparatus or device, a portable computer diskette (magnetic), a randomaccess memory (RAM) (magnetic), a read-only memory (ROM) (magnetic), anerasable programmable read-only memory (EPROM) (magnetic), a portableoptical disc such a CD, CD-R, CD-RW, DVD, DVD-R, or DVD-RW, or flashmemory such as compact flash cards, secured digital cards, USB memorydevices, memory sticks, and the like.

The firmware can also be propagated within any transport medium for useby or in connection with an instruction execution system, apparatus, ordevice, such as a computer-based system, processor-containing system, orother system that can fetch the instructions from the instructionexecution system, apparatus, or device and execute the instructions. Inthe context of this document, a “transport medium” can be any mediumthat can communicate, propagate or transport the program for use by orin connection with the instruction execution system, apparatus, ordevice. The transport readable medium can include, but is not limitedto, an electronic, magnetic, optical, electromagnetic or infrared wiredor wireless propagation medium.

It is to be understood that the computing system 200 is not limited tothe components and configuration of FIG. 2, but can include other oradditional components in multiple configurations according to variousexamples. Additionally, the components of computing system 200 can beincluded within a single device, or can be distributed between multipledevices.

As discussed above, the touch screen 220 can include touch sensingcircuitry. FIG. 3 illustrates an example touch screen including touchsensing circuitry configured as drive and sense regions or linesaccording to examples of the disclosure. Touch screen 320 can includetouch sensing circuitry that can include a capacitive sensing mediumhaving a plurality of drive lines 322 and a plurality of sense lines323. It should be noted that the term “lines” is sometimes used hereinto mean simply conductive pathways, as one skilled in the art willreadily understand, and is not limited to elements that are strictlylinear, but includes pathways that change direction, and includespathways of different size, shape, materials, etc. Additionally, thedrive lines 322 and sense lines 323 can be formed from smallerelectrodes coupled together to form drive lines and sense lines. Drivelines 322 can be coupled to transmit circuitry and sense lines 323 canbe coupled to receive circuitry. As used herein, an electrical component“coupled to” or “connected to” another electrical component encompassesa direct or indirect connection providing electrical path forcommunication or operation between the coupled components. Thus, forexample, drive lines 322 may be directly connected to transmit circuitryor indirectly connected to sense circuitry via drive interface 324, butin either case an electrical path may be provided for drivingstimulation signals to drive lines. Likewise, sense lines 323 may bedirectly connected to sense channels or indirectly connected to sensechannels via sense interface 325, but in either case an electrical pathmay be provided for sensing the sense lines 323. Drive lines 322 can bedriven by stimulation signals from the transmit circuitry 214 through adrive interface 324, and resulting sense signals generated in senselines 323 can be transmitted through a sense interface 325 to sensechannels in receive circuitry 208 in touch controller 206. In this way,drive lines and sense lines can be part of the touch sensing circuitrythat can interact to form capacitive sensing nodes, which can be thoughtof as touch nodes, such as touch nodes 326 and 327. This way ofunderstanding can be particularly useful when touch screen 320 is viewedas capturing an “image” of touch (or “touch image”). In other words,after touch controller 206 has determined whether a touch has beendetected at each touch node in the touch screen, the pattern of touchpixels in the touch screen at which a touch occurred can be thought ofas an “image” of touch (e.g., a pattern of fingers or other objectstouching the touch screen).

It should be understood that the row/drive and column/sense associationscan be exemplary, and in other examples, columns can be drive lines androws can be sense lines. In some examples, row and column electrodes canbe perpendicular such that touch nodes can have x and y coordinates,though other coordinate systems can also be used, and the coordinates ofthe touch nodes can be defined differently. It should be understood thattouch screen 220 can include any number of row electrodes and columnelectrodes to form the desired number and pattern of touch nodes. Theelectrodes of the touch sensor panel can be configured to performvarious scans including some or all of row-column and/or column-rowmutual capacitance scans, differential mutual capacitance scans,self-capacitance row and/or column scans, row-row mutual capacitancescans, column-column mutual capacitance scans, and stylus scans.

Additionally or alternatively, the touch screen can include touchsensing circuitry including an array of touch node electrodes arrangedin a pixelated touch node electrode configuration. FIG. 4 illustrates anexample touch screen including touch sensing circuitry configured aspixelated touch node electrodes according to examples of the disclosure.Touch screen 420 can include touch sensing circuitry that can include aplurality of individual touch node electrodes 422, each touch nodeelectrode identifying or representing a unique location on the touchscreen at which touch or proximity (i.e., a touch or proximity event) isto be sensed, and each touch node electrode being electrically isolatedfrom the other touch node electrodes in the touch screen/panel. Touchnode electrodes 408 can be on the same or different material layers ontouch screen 420. In some examples, touch screen 420 can sense theself-capacitance of touch node electrodes 422 to detect touch and/orproximity activity on touch screen 420. For example, in aself-capacitance configuration, touch node electrodes 422 can be coupledto sense channels in receive circuitry 208 in touch controller 206, canbe driven by stimulation signals from the sense channels (or transmitcircuitry 214) through drive/sense interface 425, and can be sensed bythe sense channels through the drive/sense interface as well, asdescribed above. Labeling the conductive plates used to detect touch(i.e., touch node electrodes 422) as “touch pixel” electrodes can beparticularly useful when touch screen 420 is viewed as capturing an“image” of touch. In other words, after touch controller 206 hasdetermined an amount of touch detected at each touch node electrode 422in touch screen 420, the pattern of touch node electrodes in the touchscreen at which a touch occurred can be thought of as an “image” oftouch (e.g., a pattern of fingers or other objects touching the touchscreen). In some examples, touch screen 420 can sense the mutualcapacitance between touch node electrodes 422 to detect touch and/orproximity activity on touch screen 420 Although discussed hereinprimarily with reference to a row-column touch sensor panel (e.g., withreference to FIGS. 6A-6C), the principles of the common mode noisecorrection can be applied to a pixelated touch sensor panel configuredto detect mutual capacitance. Additionally, although discussed hereinprimarily with reference to mutual capacitance based touch sensorpanels, the principles of the common mode noise correction can beapplied to other capacitance based touch sensor panels (e.g.,self-capacitance based touch sensor panels), resistive touch sensorpanels, and other types of touch sensor panels. Additionally, it shouldbe understood that a force sensor panel can also be implemented usingmutual capacitance sensing techniques. In some examples, force sensorpanel can measure mutual capacitance between electrodes mounted on thebackplane of the display and electrodes mounted on a proximate flexcircuit. As force is exerted, the distance between the electrodesmounted on the backplane of the display and electrodes mounted on aproximate flex circuit can change the mutual capacitance couplingtherebetween. The change in mutual capacitance can be measured to detectforce applied to the touch screen.

FIG. 5 illustrates an example mutual capacitance scan of an examplerow-column touch sensor panel. Touch sensor panel 500 can include anarray of touch nodes formed at the crossing points of row electrodes 510and column electrodes 520. For example, touch node 506 can be formed atthe crossing point of row electrode 501 and column electrode 502. Duringa single-stimulation mutual capacitance scan, a row electrode 501(configured as a drive line) can be coupled to the transmit circuitry214 which can stimulate the row electrode 501 with a drive signal(“Vstim”). One or more column electrodes (configured as sense lines) canbe coupled to the receive circuitry 208 to sense mutual capacitance (orchanges in mutual capacitance) between row electrode 501 and each of theone or more column electrodes. For each step of the single-stimulationmutual capacitance scan, one row electrode can be stimulated and the oneor more column traces can be sensed. A touch node 506 can have a mutualcapacitance Cm at the touch node 506 (between stimulated row electrode501 and sensed column electrode 502) when there is no object touching orproximate to (e.g., within a threshold distance of) touch node 506. Whenan object touches or is proximate to the touch node 506 (e.g., a fingeror stylus), the mutual capacitance Cm can be reduced by ΔCm. i.e.,(Cm−ΔCm), corresponding to the amount of charge shunted through theobject to ground. This mutual capacitance change can be sensed by senseamplifier 508 in the receive circuitry 208, which can be coupled to thecolumn electrode 502 corresponding to touch node 506, to sense a touchsignal that can be used to indicate the touch or proximity of an objectat touch node 506. The sensing described with respect to touch node 506can be repeated for the touch nodes of the touch sensor panel togenerate an image of touch for the touch sensor panel (e.g., insubsequent single-stimulation mutual capacitance steps different rowelectrodes, such as row electrodes 503, 505, and 507, can bestimulated). In examples with a dedicated sense amplifier 508 for eachcolumn electrode (sense line) and N row electrodes (drive lines), thetouch image for the touch sensor panel can be generated using Nsingle-stimulation mutual capacitance scan steps.

In some examples, rather than using a single-stimulation mutualcapacitance scan, the row-column touch sensor panel 500 can bestimulated using a multi-stimulation (“multi-stim”) mutual capacitancescan. In multi-stim scan, multiple drive lines (e.g., row electrodes510) can be simultaneous stimulated with different stimulation signalsfor multiple stimulation steps, and the sense signals generated at oneor more sense lines (e.g., column electrodes 520) in response to themultiple stimulation steps can be processed to determine the presenceand/or amount of touch for each touch node in the touch sensor panel(corresponding to the multiple drive lines). For example, FIG. 5illustrates four row electrodes 510 and four column electrodes 520. Insome examples, each of the four row electrodes 510 can be stimulatedwith a drive signal Vstim, but the phases of the drive signals appliedto the drive lines can be different for four stimulation steps. In someexamples, the drive signal can be in-phase (Vstim+, 0° phase) orout-of-phase (Vstim−, 180° phase). For example, the polarities of thestimulation signals (e.g., cosine of the phase) for two examplemulti-stim scans can be represented by Table 1 or Table 2:

TABLE 1 Step 1 Step 2 Step 3 Step 4 Row 501 + + + + Row 503 + + − − Row505 + − − + Row 507 + − + −

TABLE 2 Step 1 Step 2 Step 3 Step 4 Row 501 − + − + Row 503 + + − − Row505 + − + − Row 507 − − + +For each sense line and for each step, the sensed signal can includecontributions from the four drive lines (e.g., due to the capacitivecoupling between the four drive lines and the sense line), encoded basedon the polarity of the stimulation signal. At the end of the four steps,four sensed signals for a respective sense line can be decoded based onthe stimulation phases to extract the capacitive signal for each touchnode formed by one of the drive lines and the respective sense line. Forexample, assuming a linear system, the sensed signal for a sense linefor each scan step can be proportional to the total signal charge,Q_(sig_tot), which can be equal to the sum of the product of thestimulation voltage and the touch node capacitance for each touch nodeof the sense line. Mathematically, this can be expressed for step S byequation (1) as:Q _(sig_tot)(S)=Σ_(i=0) ^(M) Vstim_(i)(S)·Csig_(i)  (1)where Vstim can represent the stimulation voltage indexed for drive line(row electrode) i and step S and Csig can represent the capacitance ateach touch node for the sense line indexed for corresponding drive line(row electrode) i. In vector form, the above expression can be rewrittenin equation (2) as:{tilde over (Q)} _(sig_tot)=Vstim·{tilde over (M)}·{tilde over(C)}sig  (2)where {tilde over (Q)}_(sig_tot) can represent a vector of the sensedsignals from each scan step of the multi-stim scan, Vstim can representa constant stimulation voltage, {tilde over (M)} can represent a matrixof polarities of the stimulation voltage (stimulation matrix) indexed byrow and step (e.g., as shown in Table 1 or Table 2 above), and Csig canrepresent a vector of the capacitance at each touch node for the senseline. The capacitance value at each touch node of the sense line can bedecoded using equation (3):

$\begin{matrix}{{\overset{˜}{C}{sig}} = {\frac{{\overset{\sim}{M}}^{- 1}}{Vstim} \cdot {\overset{\sim}{Q}}_{{sig}\;\_\;{tot}}}} & (3)\end{matrix}$where {tilde over (M)}⁻¹ can represent the inverse of stimulationmatrix. Repeating the measurements and calculations above for each senseline can determine a capacitance signal for each touch node of the touchsensor panel scanned during the multi-stim scan. Although the multi-stimscan described above with respect to FIG. 5 includes four scan steps, itshould be understood that the total duration of all four scan steps ofthe multi-stimulation scan can be the same duration as each scan step ofthe single-stimulation scan without any reduction in the integrationtime for sensing the capacitive signal at each touch node. Additionaldiscussion of multi-stimulation touch sensing can be found in U.S. Pat.No. 7,812,827 entitled “Simultaneous Sensing Arrangement” by SteveHotelling, et al. (filed Jan. 3, 2007) and in U.S. Pat. No. 8,592,697entitled “Single-Chip Multi-Stimulus Sensor Controller” by SteveHotelling, et al. (filed Sep. 10, 2008) both of which are incorporatedby reference herein.

FIG. 9 illustrates an example stackup of a touch screen 900 according toexamples of this disclosure. In some example, touch screen 900 can haveone or more touch circuitry layers, including touch sensor panel layer902, and one or more display circuitry layers (e.g., of an LED or OLEDdisplay) including a cathode layer 904 and display data layer 906. Insome examples, touch sensor panel layer 902 can include touch sensorpanels in accordance with examples of this disclosure (e.g., patternedtouch electrodes), for example as illustrated and described with respectto FIGS. 3 and 4. In some examples, touch sensor panel layer 902includes columns of touch electrodes and rows of touch electrodes (e.g.,formed by diamond-shaped electrodes 903A-D, connections not shown). Insome examples, display data layer 906 can include a plurality of displaydata lines 907A-D. In some examples, the display data lines provide dataand/or drive elements of the LED or OLED display (e.g., to display animage). In some examples, the display data lines 907A-D can be routed inparallel to the columns of touch electrodes and perpendicular to the rowof touch electrodes (e.g., as illustrated with respect to FIG. 6A, wherea column of split sense electrodes 602 and 604 are disposed parallel todisplay data line 620 and row of drive electrodes, e.g., drive electrode606 are disposed perpendicular to display data line 620). It isunderstood that although FIG. 9 illustrates one display data linedisposed under each of the column of touch electrodes, multiple displaydata lines can be disposed beneath the columns of split sense electrodes(e.g., one or more display data line under each column or one or moredisplay data lines under one or more of the columns). In some example,when display data lines 907A-D can be driven (e.g., with a stimulationvoltage or current), noise can be capacitively coupled onto touchelectrodes 903A-D via cathode layer 904 (e.g., the stimulation signalcan couple from the display data lines 907A-D to the cathode layer 904and from cathode layer 904 to touch electrodes 903A-D). As the distancebetween display data lines 907A-D and touch electrodes 903A-D decreases,the amount of noise coupling between the display layers and the touchlayers can increase. In some example, the noise experienced by a touchelectrode from an underlying display data line can be the same orsimilar across the entire length of the touch electrode (e.g., acolumn). In other words, the noise experienced by one portion of a touchelectrode can be the same or similar to the noise experienced by anotherportion of the touch electrode. Thus, the noise experienced by the touchelectrodes from the display data lines can be “common mode noise.”

As described herein, in some examples, differential banked sensing ofpatterned electrodes with a split sense line configuration can be usedto reduce display noise coupling into touch sensing measurements. FIG.6A illustrates a portion of an example touch screen 600 according toexamples of the disclosure. In some examples, touch screen 600 caninclude patterned touch electrodes (e.g., row touch electrodes formingdrive lines and column touch electrodes forming sense lines) configuredfor measuring touch (or proximity) of an object to touch screen 600.Additionally, touch screen 600 can include display data lines (e.g.,display electrodes) configured to provide the data to display pixels todisplay an image on touch screen 600. For ease of description, onedisplay data line 620, one column of split sense electrodes 602 and 604(e.g., formed from patterned diamond electrodes 602A-D and 604A-D,respectively) and an overlapping portion of multiple rows of driveelectrodes 606, 608, 610, 612, 614, 616, 618 and 619 (e.g., formed frompatterned diamond electrodes 606A-B, 608A-B, 610A-B, 612A-B, 614A-B,616A-B, 618A-B and 619A-B, respectively). Sense electrodes 602 and 604can be electrically isolated from one another and not electricallycoupled. Although FIG. 6A illustrates splitting the column into twosense electrodes 602 and 604, in some examples, the column can bedivided or otherwise split into more than two sense electrodes.Additionally although groups of four drive electrodes are illustrated,it should be understood that the groups can include fewer electrodes(e.g., 2 electrodes) or more electrodes (e.g., 8 electrodes, etc.).

As illustrated in FIG. 6A, in some examples, display data line 620 canbe disposed beneath the column of split sense electrodes 602 and 604. Itis understood that although one display data line 620 is illustrated,touch screen 600 can have multiple display data lines disposed beneath(e.g., according to the stackup of layers in FIG. 9) the columns ofsplit sense electrodes (e.g., one or more display data lines under eachcolumn, or one or more display data lines under one or more of thecolumns). In some examples, display data line 620 can be disposed abovethe column of split sense electrodes 602 and 604, and otherwise parallelto the column of split sense electrodes 602 and 604 (e.g., andperpendicular to the drive electrodes). In some examples, the displaydata line 620 can also be disposed beneath a portion of the rowelectrodes. Other widths of display data line 620 are possible withoutdeparting from the scope of this disclosure. In some examples, displaydata line 620 can be separated from split sense electrodes 602 and 604by one or more layers (e.g., a dielectric layer, a cathode layer, or anyother potential display stackup layers). In some examples, the proximityof display data line 620 to the column of split sense electrodes 602 and604 can introduce noise from the display data line (or other noisesources) into the column of split sense electrodes 602 and 604 (e.g.,via capacitive or other parasitic coupling mechanism) when display dataline 620 is updating or otherwise driving a display. In some examples,the noise introduced by display data line 620 can be common mode noiseintroduced into sense electrode 602 and into sense electrode 604. Insome examples, the arrangement of the display data line 620 in parallelwith split sense electrode 602 and split sense electrode 604 can allowfor improved correlation of noise sensed by split sense electrode 602and split sense electrode 604 (e.g., as compared to when display dataline 620 is perpendicular to split sense electrode 602 and split senseelectrode 604). Thus, the common mode noise introduced into senseelectrode 602 and into sense electrode 604 by display data line 620 canbe the same as or similar to each other. As described in more detailbelow, by splitting the column into split sense electrodes 602 and 604,the common mode noise injected by the display can be mitigated orreduced.

The rows of drive electrodes and the column of sense electrodesillustrated in FIG. 6A can be coupled to touch circuitry (e.g., touchcontroller 206) via a drive and/or sense interface (e.g., driveinterface 324, sense interface 325 and/or drive/sense interface 425). Insome examples, the rows of drive electrodes can be coupled to transmitcircuitry (e.g., transmit circuitry 214). In some examples, groups ofmultiple rows of drive electrodes can be coupled to a drive circuitconfigured to generate multi-stim drive signals for a bank. For example,FIG. 6A illustrates drive electrodes 606, 608, 610 and 612 (of a firstbank 628) coupled to drive circuit 622 and drive electrodes 614, 616,618 and 619 (of a second bank 629) can be coupled to drive circuit 624.Although illustrated as two distinct circuits, it is understood thatdrive circuit 622 and drive circuit 624 can be integrated into a singledrive circuit. In some examples, to reduce drive circuitry, driveelectrodes 606, 608, 610 and 612 can be coupled (e.g., via switchingcircuitry, such as a multiplexer, not shown) to drive circuit 622 duringa first phase of a touch scan and drive electrodes 614, 616, 618 and 619can be coupled (e.g., via switching circuitry, such as a multiplexer,not shown) to drive circuit 622 during a second phase of the touch scan(with drive circuit 624 omitted).

An exemplary method of stimulating and sensing the drive and senseelectrodes, respectively, will now be described. For example, a mutualcapacitance scan to generate a touch image for touch screen 600 can bedivided into two phases. During a first phase of a mutual capacitancescan, the drive electrodes in the first bank 628 can be driven in afirst set of steps (e.g., corresponding to the stimulation matrixillustrated in Table 1 or Table 2) and a mutual capacitance or change inmutual capacitance between the drive electrodes of the first bank 628and sense electrode of the first bank 628 (e.g., sense electrodes 602)can be measured. During a second phase of the mutual capacitance scan,the drive electrodes in the second bank 629 can be driven in a secondset of steps (e.g., corresponding to the stimulation matrix illustratedin Table 1 or Table 2) and a mutual capacitance or change in mutualcapacitance between the drive electrodes of the second bank 629 andsense electrode of the second bank 629 can be measured. During the firstphase of the mutual capacitance scan the drive electrodes in the secondbank 629 can be unstimulated (or grounded or otherwise stimulated with aDC signal) and noise for sense electrode of the second bank 629 can bemeasured, and during the second phase of the mutual capacitance scan thedrive electrodes in the first bank 628 can be unstimulated (or groundedor otherwise stimulated with a DC signal) and noise for the senseelectrode of the first bank 628 can be measured. During the first phaseof the mutual capacitance scan, sense circuit 626 (e.g., correspondingto receive circuitry 208) can sense split sense electrodes 602 and 604(e.g., simultaneously or nearly simultaneously within a threshold periodof time). Likewise, during the second phase of the mutual capacitancescan, sense circuit 626 can sense split sense electrodes 602 and 604.

The sensing during the first phase of the mutual capacitance scan canmeasure capacitances of touch nodes of the first bank 628 correspondingto sense electrode 602 that can include a touch signal indicative of anobject touching or proximate (within a threshold distance) of touchscreen 600 and can include noise injected by display data line 620 andcoupled onto sense electrode 602. The sensing during the first phase ofthe mutual capacitance scan can measure capacitances of touch nodes ofthe second bank 629 corresponding to sense electrode 604 that caninclude the noise injected by display data line 620 without a touchsignal indicative of an object touching or proximate to touch screen 600(e.g., because the drive electrodes in the second bank 629 areunstimulated during the first phase of the mutual capacitance scan). Insome examples, the noise detected by sense electrodes 602 and 604 fromthe display data line 620 can be the same (or similar, e.g., within athreshold voltage level). As described herein, this noise can bereferred to as “common-mode noise” because the noise appears in the same(or similar) manner on both sense electrodes 602 and 604. In someexamples, sense circuit 626 can subtract the signal from the second bank629 from the signal from the first bank 628 (e.g., using single ended ordifferential circuitry illustrated in FIGS. 7A-7E). Because the secondbank 629 experiences the same (or similar) common mode noise as thefirst bank 628, subtracting the signal of the second bank 629(representative of noise) from the signal of the first bank 628(representative of the touch signal and noise) can eliminate or reducethe common mode noise.

In a similar manner, the sensing during the second phase of the mutualcapacitance scan can measure capacitances of touch nodes of the secondbank 629 corresponding to sense electrode 604 that can include a touchsignal indicative of an object touching or proximate (within a thresholddistance) of touch screen 600 and can include noise injected by displaydata line 620 and coupled onto sense electrode 604. The sensing duringthe second phase of the mutual capacitance scan can measure capacitancesof touch nodes of the first bank 628 corresponding to sense electrode602 that can include the noise injected by display data line 620 withouta touch signal indicative of an object touching or proximate to touchscreen 600. In some examples, the noise detected by sense electrodes 602and 604 from the display data line 620 can be “common-mode noise.” Insome examples, sense circuit 626 can subtract the signal from the firstbank 628 from the signal from the second bank 629 (e.g., using singleended or differential circuitry illustrated in FIGS. 7A-7E). Because thefirst bank 628 experiences the same (or similar) common mode noise asthe second bank 629, subtracting the signal of the first bank 628(representative of noise) from the signal of the second bank 629(representative of the touch signal and noise) can eliminate or reducethe common mode noise.

As a result of the first and second phases, and the subtraction of thecommon mode noise from capacitive measurements of the first and secondbanks, the resulting signals at the touch nodes of the first and secondbanks can capture a touch “image” of the first and second banks(corresponding to the column of sense electrodes 602 and 604 and themultiple rows of drive electrodes 606, 608, 610, 612, 614, 616, 618,619) filtered for common mode noise. The same measurements andsubtraction can be repeated for the rest of the columns (by sensecircuits similar sense circuit 626) of the touch sensor panel of touchscreen 600 to form the touch image for touch screen 600 for furtherprocessing to identify and process touch input.

FIG. 6B illustrates a portion of an example touch screen 630 accordingto examples of the disclosure. In some examples, touch screen 630 caninclude patterned touch electrodes (e.g., column touch electrodesforming drive lines and row touch electrodes forming sense lines)configured for measuring touch (or proximity) of an object to touchscreen 630. Additionally, touch screen 630 can include display datalines (e.g., display electrodes) configured to provide the data todisplay pixels to display an image on touch screen 630. For ease ofdescription, one display data line 650, four columns of split driveelectrodes 631, 632, 633, 634, 636, 637, 638 and 639 (e.g., formed frompatterned diamond electrodes) and an overlapping portion of multiplerows of sense electrodes 640, 641, 642, 645, 646 and 647 (e.g., formedfrom patterned diamond electrodes). Drive electrodes in each column(e.g., 631 and 636, 632 and 637, 633 and 638, and 634 and 639) can beelectrically isolated from one another and not electrically coupled.Although FIG. 6B illustrates splitting each column into two driveelectrodes, in some examples, the columns can be divided or otherwisesplit into more than two drive electrodes. Additionally although groupsof four drive electrodes are illustrated, it should be understood thatthe groups can include fewer electrodes (e.g., 2 electrodes) or moreelectrodes (e.g., 8 electrodes, etc.).

As illustrated in FIG. 6B, in some examples, display data line 650 canbe disposed beneath at least one column of split drive electrodes 631and 636. It is understood that although one display data line 650 isillustrated, touch screen 630 can have multiple display data linesdisposed beneath the columns of split drive electrodes (e.g., one ormore display data lines under each column or one or more display datalines under one or more of columns of split drive electrodes 632 and637, 633 and 638, and 634 and 639). In some examples, display data line650 can be disposed above the column of split drive electrodes 631 and636, or otherwise parallel to the column of split drive electrodes 631and 636 (e.g., and perpendicular to the sense electrodes). In someexamples, the display data line 650 can also be disposed beneath aportion of one or more row electrodes. Other widths of display data line650 are possible without departing from the scope of this disclosure. Insome examples, display data line 650 can be separated from split driveelectrodes 631 and 636 by one or more dielectric layers or a cathodelayer). In some examples, the proximity of display data line 650 to thecolumn of split drive electrodes 631 and 636 can introduce noise fromthe display data line (or other noise sources) into the column of splitdrive electrodes 631 and 636 (e.g., via capacitive or other parasiticcoupling mechanism) and into rows of sense electrodes (e.g., directly orindirectly by perturbing the stimulation waveform on the driveelectrodes which can be detected by the sense electrodes and translatedinto noise in the capacitance or change in capacitance measurements)when display data line 650 is updating or otherwise driving a display.In some examples, the noise introduced by display data line 650 can becommon mode noise introduced into sense electrodes (e.g., senseelectrodes 640 and 645. As described in more detail below, by splittingthe columns into split drive electrodes (e.g., 631 and 636) and drivingthe split drive electrodes of different banks with different codedstimulation signals, the common mode noise injected by the display canbe mitigated or reduced.

The column of drive electrodes and the rows of sense electrodesillustrated in FIG. 6B can be coupled to touch circuitry (e.g., touchcontroller 206) via a drive and/or sense interface (e.g., driveinterface 324, sense interface 325 and/or drive/sense interface 425). Insome examples, the column of drive electrodes can be coupled to transmitcircuitry (e.g., transmit circuitry 214). In some examples, groups ofmultiple split drive electrodes can be coupled to a drive circuitconfigured to generate multi-stim drive signals for a bank. For example,FIG. 6B illustrates split drive electrodes 631, 632, 633 and 634 (of afirst bank 658) coupled to drive circuit 652 and split drive electrodes636, 637, 638 and 639 (of a second bank 659) can be coupled to drivecircuit 654. Although illustrated as two distinct circuits, it isunderstood that drive circuit 652 and drive circuit 654 can beintegrated into a single drive circuit.

An exemplary method of stimulating and sensing the drive and senseelectrodes, respectively, will now be described. For example, a mutualcapacitance scan can generate a touch image for touch screen 630 duringone simultaneous drive/sense phase (e.g., as opposed to two distinctphases described above with respect to FIG. 6A). In some examples, thedrive electrodes in the first bank 658 can be driven in a first set ofsteps (e.g., using a first set of coded stimulation signals) and amutual capacitance or change in mutual capacitance between the driveelectrodes of the first bank and one row of sense electrodes of thefirst bank 658 (e.g., sense electrode 640) can be measured. Concurrentlywith driving and sensing electrodes of the first bank 658, the driveelectrodes in the second bank 659 can be driven in a second set of steps(e.g., using a second, orthogonal set of coded stimulation signals) anda mutual capacitance or change in mutual capacitance between the driveelectrodes of the second bank 659 and a row of sense electrodes of thesecond bank 659 (e.g., sense electrode 645) can be measured. In someexamples, sense circuit 656 (e.g., corresponding to receive circuitry208) can sense sense electrodes 640 and 645 (e.g., simultaneously ornearly simultaneously within a threshold period of time).

In some examples, the sensing of the mutual capacitance scan can measurecapacitances of touch nodes of the first bank 658 corresponding to senseelectrode 640 that can include a touch signal indicative of an objecttouching or proximate (within a threshold distance) of touch screen 630and can include noise injected by display data line 650 and coupled ontosense electrode 640. Similarly, the sensing of the mutual capacitancescan can measure capacitances of touch nodes of the second bank 659corresponding to sense electrode 645 that can include noise injected bydisplay data line 650 and coupled onto sense electrode 645. In someexamples, the noise detected by sense electrodes 640 and 645 from thedisplay data line 650 can be the same (or similar, e.g., within athreshold voltage level). As described herein, this noise can bereferred to as “common-mode noise” because the noise appears in the same(or similar) manner on both sense electrodes 640 and 645. In someexamples, sense circuit 656 can subtract the signal from the second bankfrom the signal from the first bank (e.g., using single ended ordifferential circuitry illustrated in FIGS. 7A-7E). Because the secondbank experiences the same (or similar) common mode noise as the firstbank, subtracting the signal of the second bank (representative ofnoise) from the signal of the first bank (representative of the touchsignal and noise) can eliminate or reduce the common mode noise.

As a result of the driving/sensing the first and second banks, and thesubtraction of the common mode noise from capacitive measurements of thefirst and second banks, the resulting signals at the touch nodes of thefirst and second banks can capture a touch “image” of the first andsecond bank (corresponding to the column of split drive electrodes 631,632, 633, 634, 636, 637, 638 and 639 and the two rows of senseelectrodes 640 and 645) filtered for common mode noise. The samemeasurements and subtraction can be repeated for the rest of the rows(by sense circuits similar sense circuit 656) of the touch sensor panelof touch screen 630 (e.g., for row sense electrodes 641 and 646 and rowsense electrodes 642 and 647) to form the touch image for touch screen630 for further processing to identify and process touch input. Itshould be understood that although the differential measurements areshown between equally spaced sense electrodes (e.g., the uppermost senseelectrode of the first bank and the uppermost sense electrode of thesecond bank), differential measurements between sense electrodes can bedifferent in some examples (e.g., a differential measurement of theuppermost sense electrode of the first bank and the lowermost senseelectrode of the second bank).

The above-described method of stimulating and sensing the drive andsense electrodes assumes that an object is touching or proximate to oneof the two row electrodes, but not both row electrodes simultaneously.However, it is understood that the use of different multi-stim codes canenable similar differential measurements in the scenario in which aplurality of objects is touching or proximate to both rows in the firstand second bank of electrodes, touch screen 630 can capture a touch“image” of the first and second bank, including measurement of theplurality of touching or proximate objects, filtered for common modenoise. For example, touch screen 630 can be stimulated using amulti-stimulation mutual capacitance scan, with different codedmulti-stimulation signals applied to split drive lines in each bank. Insome examples, drive circuit 652 can drive the first bank of four splitdrive electrodes according to a first multi-stimulation code and drivecircuit 654 can drive the second bank of four split drive electrodesaccording to a second different, orthogonal multi-stimulation steps,shown below in Table 3.

TABLE 3 Step Step Step Step Step Step Step Step 1 2 3 4 5 6 7 8 Column631 + + + + + + + + Column 632 + − + − + − + − Column 633 + + − − + + −− Column 634 + − − + + − − + Column 636 + + + + − − − − Column 637 + − +− − + − + Column 638 + + − − − − + + Column 639 + − − + − + + −

In some examples, driving the two banks with different, orthogonal setsof coded multi-stimulation drive signals in eight scan steps cangenerate eight sensed signals (differential sensed signals). For eachscan step, one sensed signal (including coded signal contributions fromfour drive lines (e.g., one charge on each of the four drive lines)) canbe generated on the sense electrode for each respective bank. Thus, insome examples, the sensed signals for a first bank can be generatedusing unique multi-stim codes that are orthogonal to the uniquemulti-stim codes used for generating the sensed signals for the secondbank. In some examples, because the sensed signals from the first bankare generated using orthogonal and unique stimulation signals differentthan used to for generating the sensed signals from the second bank,when sensed signals from the first bank and the second bank are combined(e.g., via a differential amplifier or other differential circuit),capacitive signals (e.g., indicative of touch) on a first bank can beorthogonal to and not conflict or interfere with capacitive signals(e.g., indicative of touch) on the second bank (e.g., by sense circuit656 when performing common mode noise elimination or reduction). In someexamples, the eight sensed signals can be processed by sense circuit 656to identify the common mode noise components and eliminate or reduce thecommon mode noise to generate eight filtered sense signals (e.g., thecommon mode noise coupled onto the sense signals of both banks are notorthogonal and can be eliminated or reduced by the sense circuits). Insome examples, a differential amplifier in sense circuit 656 can compare(e.g., combine) touch signals from the two banks (e.g., sense electrodes640 and 645) and output a differential output which filters out thecommon mode noise experienced by both banks. In some examples, the eightfiltered sensed signals can be decoded based on the stimulation phasesto extract the capacitive signal for each touch node by one of the drivelines and the respective sense line. In some examples, a touch image fortouch screen 630 can be generated using the decoded sense signals andcan be further processed to identify and process the touch input. Forexample, equation (3) described above with reference to four drive linemulti-stim example of FIG. 5, can be modified (assuming similar gain forthe sense channels) and used for decoding the sense signal in adifferential (eight drive lines) multi-stim example. The modification toequation (3) can include a difference in how the total charge ismeasured. In the four drive line multi-stim example, the total chargecan be added at the sense line. For a differential multi-stim example,the total charge for the differential sense signal (e.g., the differencebetween sense electrodes 640 and 645 of banks 658 and 659), can be adifference between the total charge accumulated for the sense electrodeof a first bank from the stimulus applied to the drive electrodes (totalcharge on sense electrode 640 from stimulation on drive electrodes631-634) and the total charge accumulated for the sense electrode of thesecond bank from the stimulus applied to the drive electrodes (e.g.,total charge on sense electrode 645 from stimulation on drive electrodes636-639) during the first half of the stimulation steps. The totalcharge for the differential sense signal can be a difference between thetotal charge accumulated for the sense electrode of the second bank fromthe stimulus applied to the drive electrodes (total charge on senseelectrode 645 from stimulation on drive electrodes 636-639) and thetotal charge accumulated for the sense electrode of the first bank fromthe stimulus applied to the drive electrodes (e.g., total charge onsense electrode 640 from stimulation on drive electrodes 631-634) duringthe second half of the stimulation steps. Because the negative input ofa differential amplifier can cause an inversion, the results from thesecond half of the stimulation steps (for the second bank) can beinverted after applying the inverse stimulation matrix of equation (3).Additionally, although Table 3 does not account for the inversion of thedifferential amplifier, in some examples, the polarities of thestimulation signals can be inverted such that the results of thedemodulation with the inverse stimulation matrix can have the properpolarities without having to invert the results for the second bank.

In FIG. 6B, rows in the first and second bank may be at a distance fromone another and as a result, there may be differences in the common modenoise. In some examples, the common mode noise elimination or reductioncan be improved by taking a differential measurement from adjacent senseelectrodes that may be collocated and have more correlated common modenoise. It is understood that although adjacent sense electrodes areillustrated in FIG. 6C as adjacent, that the differential measurementmay be between different measurements (e.g., to optimize the common modenoise cancellation). FIG. 6C illustrates a portion of an example touchscreen 660 according to examples of the disclosure. In some examples,similarly to touch screen 630, touch screen 660 can include patternedtouch electrodes (e.g., column touch electrodes forming drive lines androw touch electrodes forming sense lines) configured for measuring touch(or proximity) of an object to touch screen 660. Additionally, touchscreen 660 can include display data lines (e.g., display electrodes)configured to provide the data to display pixels to display an image ontouch screen 660. For ease of description, one display data line 680,four columns of split drive electrodes 661, 662, 663, 664, 666, 667,668, and 669 (e.g., formed from patterned diamond electrodes) and anoverlapping portion of multiple rows of sense electrodes 670, 671, 672,673, 674, and 675 (e.g., formed from patterned diamond electrodes). Asshown in FIG. 6C, patterned diamond electrodes of split drive electrodes662 and 664 can be interleaved. For example, a column of split driveelectrodes 662 and 664 can be arranged in the following order: a firstpatterned diamond electrode from drive electrode 662 (e.g., of the firstbank), a first patterned diamond electrode from drive electrode 664(e.g., of the second bank of drive electrodes), a second patterneddiamond electrode from drive electrode 662 (e.g., of the first bank), asecond patterned diamond electrode from drive electrode 664 (e.g., ofthe second bank), a third patterned diamond electrode from driveelectrode 662 (e.g., of the first bank), and a third patterned diamondelectrode from drive electrode 664 (e.g., of the second bank). Thus, asshown, electrodes of the first bank of drive electrodes and electrodesof the second bank of drive electrodes can be arranged alternately. Aswill be explained below, arranging the electrodes from the first andsecond bank alternately can enable sensing adjacent rows of senseelectrodes. Sensing adjacent rows of sense electrodes can increase thecorrelation of the common mode noise between the two rows of senseelectrodes (e.g., because the two sense rows are spaced closer together,the two sense rows can have common mode noise components that are moresimilar than when the two sense rows are at a distance from one another)and thus allow for more accurate common mode noise rejection (e.g.,elimination or reduction).

Drive electrodes in each column (e.g., 661 and 666, 662 and 667, 663 and668, 664 and 669) can be electrically isolated from one another and notelectrically coupled. Although FIG. 6C illustrates splitting the columninto two drive electrodes, in some examples, the column can be dividedor otherwise split into more than two drive electrodes. Additionallyalthough groups of four drive electrodes are illustrated, it should beunderstood that the groups can include fewer electrodes (e.g., 2electrodes) or more electrodes (e.g., 8 electrodes, etc.).

As illustrated in FIG. 6C, in some examples, display data line 680 canbe disposed beneath the column of split drive electrodes 661 and 666. Itis understood that although one display data line 680 is illustrated,touch screen 660 can have one or more display data lines disposedbeneath the columns of split drive electrodes (e.g., one or more displaydata lines under each column or one or more display data lines under oneor more of columns of split drive electrodes 662 and 667, 663 and 668,and 664 and 669). In some examples, display data line 680 can bedisposed above the column of split drive electrodes 661 and 666, orotherwise parallel to the column of split drive electrodes 661 and 666.In some examples, the display data line 680 can also be disposed beneatha portion of the one or more row electrodes. Other widths of displaydata line 680 are possible without departing from the scope of thisdisclosure. In some examples, display data line 680 can be separatedfrom split drive electrodes 661 and 666 by one or more dielectric layersor a cathode layer). In some examples, the proximity of display dataline 680 to the column of split drive electrodes 661 and 666 canintroduce noise from the display data line (or other noise sources) intothe column of split drive electrodes 661 and 666 (e.g., via capacitiveor other parasitic coupling mechanism) and into rows of sense electrodes(e.g., directly or indirectly by perturbing the stimulation waveform onthe drive electrodes which can be detected by the sense electrodes andtranslated into noise in the capacitance or change in capacitancemeasurements) when display data line 680 is updating or otherwisedriving a display. In some examples, the noise introduced by displaydata line 680 can be common mode noise introduced into drive electrode661 and into drive electrode 666. As described in more detail below, bysplitting the column into split drive electrodes 661 and 666, the commonmode noise injected by the display can be mitigated or reduced.

The column of drive electrodes and the rows of sense electrodesillustrated in FIG. 6C can be coupled to touch circuitry (e.g., touchcontroller 206) via a drive and/or sense interface (e.g., driveinterface 324, sense interface 325 and/or drive/sense interface 425). Insome examples, the column of drive electrodes can be coupled to transmitcircuitry (e.g., transmit circuitry 214). In some examples, groups ofmultiple columns of drive electrodes can be coupled to a drive circuitconfigured to generate multi-stim drive signals for a bank. For example,FIG. 6C illustrates split drive electrodes 661, 662, 663, and 664 (of afirst bank) coupled to drive circuit 682 and drive electrodes 666, 667,668, and 669 (of a second bank) can be coupled to drive circuit 684.Although illustrated as two distinct circuits, it is understood thatdrive circuit 682 and drive circuit 684 can be integrated into a singledrive circuit.

An exemplary method of stimulating and sensing the drive and senseelectrodes, respectively, will now be described. For example, a mutualcapacitance scan can generate a touch image for touch screen 660 duringone simultaneous drive and sense phase (e.g., as opposed to two distinctphases described above with respect to FIG. 6A). In some examples, thedrive electrodes in the first bank can be driven in a first set of steps(e.g., using a first set of coded stimulation signals) and a mutualcapacitance or change in mutual capacitance between the drive electrodesof the first bank and one row of sense electrodes of the first bank(e.g., sense electrodes 670) can be measured. Concurrently with drivingand sensing electrodes of the first bank, the drive electrodes in thesecond bank can be driven in a second set of steps (e.g., using asecond, orthogonal set of coded stimulation signals) and a mutualcapacitance or change in mutual capacitance between the drive electrodesof the second bank and a row of sense electrodes of the second bank(e.g., sense electrodes 671) can be measured. In some examples, sensecircuit 686 (e.g., corresponding to receive circuitry 208) can sensesplit sense electrodes 670 and 671 (e.g., simultaneously or nearlysimultaneously within a threshold period of time).

In some examples, the sensing of the mutual capacitance scan can measurecapacitances of touch nodes of the first bank corresponding to senseelectrode 670 that can include a touch signal indicative of an objecttouching or proximate (within a threshold distance) of touch screen 660and can include noise injected by display data line 680 and coupled ontodrive electrode 661. Similarly, the sensing of the mutual capacitancescan can measure capacitances of touch nodes of the second bankcorresponding to sense electrode 671 that can include noise injected bydisplay data line 680 and coupled onto sense electrode 671. In someexamples, the noise detected by sense electrodes 670 and 671 from thedisplay data line 680 can be the same (or similar, e.g., within athreshold voltage level). In some examples, sense electrodes 670 and 671can be adjacent rows of sense electrodes. In some examples, otherdistances between the two rows of sense electrodes can be used. Forexample, the two rows can be a threshold distance apart to avoidunintentionally eliminating intentional touch measurements (e.g., atouch can cause the same or similar sense signal on multiple rows ofsense electrodes which may be unintentionally identified as common modenoise and reduced or eliminated). In some examples, the noise detectedby sense electrodes 670 and 671 coupled from the display data line 680can be the same (or similar, e.g., within a threshold voltage level). Insome example, interleaving split drive electrodes 661 and 666 can enablesensing adjacent rows of sense electrodes. In some examples, adjacentrows of sense electrodes (or rows which are a certain distance apart)can increase the correlation in the noise experienced by the two rowsand thus result in better noise elimination or reduction by sensecircuit 686. As described herein, this noise can be referred to as“common-mode noise” because the noise appears in the same (or similar)manner on both sense electrodes 670 and 671. In some examples, sensecircuit 686 can subtract the signal from the second bank from the signalfrom the first bank (e.g., using single ended or differential circuitryillustrated in FIGS. 7A-7E). Because the second bank experiences thesame (or similar) common mode noise as the first bank, subtracting thesignal of the second bank (representative of noise) from the signal ofthe first bank (representative of the touch signal and noise) caneliminate or reduce the common mode noise.

As a result of the driving/sensing the first and second banks, and thesubtraction of the common mode noise from capacitive measurements of thefirst and second bank, the resulting signals at the touch nodes of thefirst and second bank can capture a touch “image” of the first andsecond bank (corresponding to the column of split drive electrodes 661,662, 663, 664, 666, 667, 668, and 669 and the two rows of senseelectrodes 670 and 671) filtered for common mode noise. The samemeasurements and subtraction can be repeated for the rest of the rows(by sense circuits similar sense circuit 686) of the touch sensor panelof touch screen 660 (e.g., for row electrodes 672 and 673 and rowelectrodes 674 and 675) to form the touch image for touch screen 660 forfurther processing to identify and process touch input. It should beunderstood that although the differential measurements are shown betweenadjacent sense electrodes, that differential measurements between senseelectrodes can be different in some examples (e.g., a differentialmeasurement of sense electrodes separated by one or more other senseelectrodes).

The above-described method of stimulating and sensing the drive andsense electrodes assumes that an object is touching or proximate to oneof the two banks, but not both banks simultaneously. However, it isunderstood that in the scenario in which a plurality of objects istouching or proximate to both the first and second bank of electrodes,touch screen 660 can capture a touch “image” of the first and secondbank, including measurement of the plurality of touching or proximateobjects, filtered for common mode noise. For example, touch screen 660can be stimulated using a multi-stimulation mutual capacitance scan,with different coded multi-stimulation signals applied to split drivelines in each bank. In some examples, drive circuit 682 can drive thefirst bank of four split drive electrodes according to a firstmulti-stimulation code and drive circuit 684 can drive the second bankof four split drive electrodes according to a second different,orthogonal multi-stimulation steps, shown above in Table 3.

In some examples, driving the two banks with different, orthogonal setsof coded multi-stimulation drive signals in eight scan steps cangenerate eight sensed signals (differential sensed signals). For eachscan step, one sensed signal (including coded signal contributions fromfour drive lines (e.g., one charge on each of the four drive lines)) canbe generated on the sense electrode for each respective bank. Thus, insome examples, the sensed signals for a first bank can be generatedusing unique multi-stim codes that are orthogonal to the uniquemulti-stim codes used for generating the sensed signals for the secondbank. In some examples, because the sensed signals from the first bankare generated using orthogonal and unique stimulation signals differentthan used to for generating the sensed signals from the second bank,when sensed signals from the first bank and the second bank are combined(e.g., via a differential amplifier or other differential circuit),capacitive signals (e.g., indicative of touch) on a first bank can beorthogonal to and not conflict or interfere with capacitive signals(e.g., indicative of touch) on the second bank (e.g., by sense circuit686 when performing common mode noise elimination or reduction). In someexamples, the eight sensed signals can be processed by sense circuit 686to identify the common mode noise components and eliminate or reduce thecommon mode noise to generate eight filtered sense signals (e.g., thecommon mode noise coupled onto the sense signals of both banks are notorthogonal and can be eliminated or reduced by the sense circuits). Insome examples, a differential amplifier in sense circuit 686 can compare(e.g., combine) touch signals from the two banks (e.g., sense electrodes670 and 671) and output a differential output which filters out thecommon mode noise experienced by both banks. In some examples, the eightfiltered sensed signals can be decoded based on the stimulation phasesto extract the capacitive signal for each touch node by one of the drivelines and the respective sense line. In some examples, a touch image fortouch screen 660 can be generated using the decoded sense signals andcan be further processed to identify and process the touch input. Forexample, equation (3) described above with reference to four drive linemulti-stim example of FIG. 5, can be modified (assuming similar gain forthe sense channels) and used for decoding the sense signal in adifferential (eight drive lines) multi-stim example. The modification toequation (3) can include a difference in how the total charge ismeasured. In the four drive line multi-stim example, the total chargecan be added at the sense line. For a differential multi-stim example,the total charge for the differential sense signal (e.g., the differencebetween sense electrodes 670 and 671), can be a difference between thetotal charge accumulated for the sense electrode of a first bank fromthe stimulus applied to the drive electrodes (total charge on senseelectrode 670 from stimulation on drive electrodes 661-664) and thetotal charge accumulated for the sense electrode of the second bank fromthe stimulus applied to the drive electrodes (e.g., total charge onsense electrode 671 from stimulation on drive electrodes 666-669) duringthe first half of the stimulation steps. The total charge for thedifferential sense signal can be a difference between the total chargeaccumulated for the sense electrode of the second bank from the stimulusapplied to the drive electrodes (total charge on sense electrode 671from stimulation on drive electrodes 666-669) and the total chargeaccumulated for the sense electrode of the first bank from the stimulusapplied to the drive electrodes (e.g., total charge on sense electrode670 from stimulation on drive electrodes 661-664) during the second halfof the stimulation steps. Because the negative input of the differentialamplifier causes inversion, the results from the second half of thestimulation steps (for the second bank) can be inverted after applyingthe inverse stimulation matrix of equation (3). Additionally, althoughTable 3 does not account for the inversion of the differentialamplifier, in some examples, the polarities of the stimulation signalscan be inverted such that the results of the demodulation with theinverse stimulation matrix can have the proper polarities without havingto invert the results for the second bank.

FIG. 6D illustrates an exemplary circuit model 690 of a touch screenaccording to examples of the disclosure. Signal sources V_(STM1) 691 andV_(STM2) 692 can represent the stimulation (e.g., drive) signals appliedto two drive electrodes (e.g., from a first and second bank,respectively) and capacitors 694 and 695 can represent the mutualcapacitance or change in capacitance between the stimulated driveelectrode and the respective sense electrode (e.g., similar to Cmdescribed above in FIG. 5). In some examples, noise source V_(CM) 693represents common mode noise introduced by one or more display datalines (e.g., routed underneath the electrodes). Using FIG. 6C as anexample, the stimulation signal on drive electrode 661 can berepresented as V_(STM1) 691 and the drive signal on drive electrode 666can be represented as V_(STM2) 692. In some examples, capacitor 694 canrepresent the mutual capacitance (e.g., capacitance or change incapacitance) created between drive electrode 661 and sense electrode 670(e.g., of the first bank) during a touch or proximity event andcapacitor 697 can represent the mutual capacitance (e.g., capacitance orchange in capacitance) created between drive electrode 666 and senseelectrode 671 (e.g., of the second bank) during a touch or proximityevent. In some examples, the common mode noise (e.g., generated by thedisplay data lines or other noise sources) that capacitively couplesonto the sense electrodes can be represented as V_(CM) 693. As shown,impedance Z_(I_N) 696 and Z_(I_N) 697 can represent the impedancecoupling (e.g., capacitive or otherwise) of the common mode noise ontothe respective sense electrodes (e.g., from the display data lines tothe cathode layer and from the cathode layer to the sense electrodes).

As shown in FIG. 6D, a common mode noise V_(CM_P) can be coupled ontothe first sense electrode and common mode noise V_(CM_N) can be coupledonto the second sense electrode. In some examples, V_(CM_P) and V_(CM_N)can have the same (or similar) magnitude. In some examples, the firstand second sense signal (e.g., including a touch event and/or commonmode noise) can be coupled to sense circuit 698. In some examples, sensecircuit 698 can include a fully differential sense amplifier 687. Insome examples, fully differential sense amplifier 687 can have variablefeedback impedance paths Z_(F_P) 688 and Z_(F_N) 689 between theinverting and noninverting inputs, respectively, and the respectivedifferential output. In some examples, Z_(F_P) 688 and Z_(F_N) 689 canbe variable impedances (e.g., comprising variable capacitors and/orvariable resistors). In some examples, Z_(F_P) 688 and Z_(F_N) 696 canbe adjusted to match the ratio of Z_(I_P) 696 and Z_(I_N) 697. In someexamples, fully differential sense amplifier 687 can be coupled to afirst sense signal on the inverting input and a second sense signal onthe noninverting input. In some examples, fully differential senseamplifier 687 can receive a DC bias voltage 685. In some examples, thedifferential output of fully differential amplifier 687 can be coupledto differential ADC 699. In some examples, differential ADC 699 canfurther remove (e.g., eliminate or reduce) any remaining common modenoise, including common mode noise not fully removed by fullydifferential amplifier 687 and common mode noise coupled onto the sensesignals by other sources or by the components of sense circuit 698.Thus, in some examples, the output of ADC 699 can be a digital signalrepresentative of the capacitance or change in capacitance with thecommon mode noise eliminated or reduced. In some examples, the resultingsignal output by ADC 699 can be processed (e.g., decoded, etc.) todetect touch and/or proximity input. In some examples, the resultingsignal can be coupled to a processor (e.g., touch processors 202, touchcontroller 206 and/or host processor 228

In some examples, the gain of fully differential amplifier 687 can becontrolled by variable impedances Z_(F_P) 688 and Z_(F_N) 689 and thecapacitance experienced by the common mode signal when coupling onto thesense lines Z_(I_P) 696 and Z_(I_N) 697. Thus, the output of fullydifferential amplifier 687 (e.g., the differential output) can bemodeled by the equation:V _(o)=−(V _(CM_N) −V _(CM_P))*G  (4)where V_(CM_N) can represent the common mode noise coupled onto thesecond sense signal, V_(CM_P) can represent the common mode noisecoupled onto the first sense signal, and G can represent the gain of thefully differential amplifier 687. In some examples, when Z_(F_P) 688 andZ_(F_N) 696 is adjusted to match the ratio of Z_(I_P) 696 and Z_(I_N)697, the gain of fully differential amplifier 687 can be modeled by theequation:

$\begin{matrix}{G = {\frac{Z_{F\;\_\; P}}{Z_{I\;\_\; P}} = \frac{Z_{F\;\_\; N}}{Z_{I\;\_\; N}}}} & (5)\end{matrix}$where Z_(F_P) can represent the impedance of feedback path Z_(F_P) 688,Z_(I_P) can represent the capacitance experienced by common mode signalZ_(I_P) 696, Z_(F_N) can represent the impedance of feedback pathZ_(F_N) 689, and Z_(I_N) can represent the capacitance experienced bycommon mode signal Z_(I_N) 697. Thus, in some examples, when V_(CM_N)and V_(CM_P) have the same magnitude, fully differential amplifier 687can eliminate (or minimize) the common mode noise coupled onto the senselines. In some examples, when V_(CM_N) and V_(CM_P) are not equal, buthave similar magnitudes, fully differential amplifier 687 can attenuate(e.g., reduce or otherwise mitigate) the common mode noise.

In some examples, sense circuit 698 can be the same or similar to sensecircuits 626, 656, and 686 and the sense circuit 698 can be implementedin any of sense circuits 626, 656, and 686. Although sense circuit 698is depicted with a particular sense circuit implementation, it isunderstood that sense circuit 698 can be implemented using any of sensecircuits 700, 720, 740, 760, or 780.

FIGS. 7A-7E illustrate example sense circuits to eliminate or reducecommon mode noise according to examples of the disclosure. FIG. 7Aillustrates an example sense circuit 700 including single-ended senseamplifiers 706 and 708, and summing circuit 710 according to examples ofthe disclosure. In some examples, single-ended sense amplifier 706(e.g., the inverting input) can be coupled to a first split senseelectrode 702 (e.g., sense electrode 602) and single-ended senseamplifier 708 (e.g., the inverting input) can be coupled to a secondsplit sense electrode 704 (e.g., sense electrode 604). The non-invertinginputs of single-ended sense amplifiers 706 and 708 can be coupled to aDC bias voltage. Single-ended sense amplifiers 706 and 708 can havefeedback network 712 and 714, respectively, coupled between the outputof the sense amplifiers and the inverting input of the sense amplifiers.In some examples, feedback networks 712 and 714 can control the gain ofsingle-ended sense amplifiers 706 and 708. In some examples the feedbacknetworks 712 and 714 can each include a resistor and/or a capacitor(e.g., with a variable resistance and/or variable capacitance) inparallel or otherwise. Thus, in some examples, feedback networks 712 and714 can have variable impedances. Summing circuit 710 can be coupled tothe output of single-ended sense amplifiers 706 and 708. In someexamples, the output of single-ended sense amplifier 706 can be coupledto the positive input of summing circuit 710 and the output ofsingle-ended sense amplifier 708 can be coupled to the negative input ofsumming circuit 710. In some examples, summing circuit 710 can comprisean analog summing circuit (e.g., the circuit adds or subtracts theanalog voltage or current levels of the inputs). In some examples,summing circuit 710 can comprise analog-to-digital converters to convertthe two analog inputs to digital values and a digital summer to add orsubtract the digital values. These and other suitable circuits toachieve the summing functionality are contemplated by this disclosure.Thus, summing circuit 710 can subtract the signal from the negativeinput (e.g., the output of single-ended sense amplifier 708) from thesignal from the positive input (e.g., the output of single-ended senseamplifier 706). In such an example, because the signals from thepositive input and negative input both contain the same or similarcommon mode noise component, subtracting the two signals can result in asignal with no or a reduced amount of common mode noise. Thus, in someexamples, the output of summing circuit 710 can be a signalrepresentative of the capacitance or change in capacitance with thecommon mode noise eliminated or reduced. In some examples, the resultingsignal output by summing circuit 710 can be processed (e.g., decoded,etc.) to detect touch and/or proximity input. In some examples, theresulting signal can be coupled to a processor (e.g., touch processors202, touch controller 206 and/or host processor 228).

It is understood that sense circuit 700 can be implemented in any ofsense circuits 626, 656, 686, and 698 described above with respect toFIGS. 6A-6D. For example, in the exemplary method of stimulating andsensing the drive and sense electrodes described in FIG. 6A, sensecircuit 700 can operate as described during the first phase of a mutualcapacitance scan. In such examples, the output of summing circuit 710can be a signal representative of the capacitance or change incapacitance of the sense electrode of the first bank. During the secondphase of a mutual capacitance scan, the inputs to single-ended senseamplifier 706 and 708 can be reversed (e.g., via switching circuitry,such as a multiplexer, not shown). For example, single-ended amplifier706 can be switched to be coupled to second split sense electrode 704(e.g., corresponding to sense electrode 604) and single-ended amplifier708 can be switched to be coupled to first split sense electrode 702(e.g., corresponding to sense electrode 602). Thus, the output ofsumming circuit 710 can be a signal representative of the capacitance orchange in capacitance of the sense electrode of the second bank. In someexamples, instead of reversing the inputs to single-ended senseamplifiers 706 and 708, the inputs of the summing circuit 710 can bereversed to achieve the same effect. For example, the positive input ofsumming circuit 710 can be switched (e.g., via switching circuitry, suchas a multiplexer, not shown) to couple to the output of single-endedsense amplifier 708 and the negative input of summing circuit 710 can beswitched (e.g., via switching circuitry, such as a multiplexer, notshown) to couple to the output of single-ended sense amplifier 706.Thus, the output of summing circuit 710 can be a signal representativeof representative of the capacitance or change in capacitance of thesense electrode of the second bank.

FIG. 7B illustrates an example sense circuit 720 including single-endedsense amplifiers 726 and 728, and common mode amplifier 730 according toexamples of the disclosure. In some examples, common mode amplifier 730can be an amplifier with two noninverting inputs, one inverting input,and two inverting outputs. In some examples, the inverting input ofcommon mode amplifier 730 can be coupled to a common mode DC biasvoltage 732. In some examples, common mode amplifier 730 can be coupledto a first split sense electrode 722 (e.g., sense electrode 602) at afirst noninverting input and a second split sense electrode 724 (e.g.,sense electrode 604) at a second noninverting input. In some examples,the two inverting outputs of common mode amplifier 730 can be coupled tothe noninverting inputs and act as a feedback loop to common modeamplifier 730. In some examples, in response to the inputs on thenoninverting input, common mode amplifier 730 can output current on theinverting outputs that have an equal (or similar) but opposite magnitudeas the common mode noise component on the noninverting inputs. Thus, insome examples, the outputs of common mode amplifier 730, coupled tofirst split sense electrode 722 and second split sense electrode 724(e.g., as a feedback mechanism), can remove, eliminate, or reduce thecommon mode noise from first split sense electrode 722 and second splitsense electrode 724. Thus, first split sense electrode 722 and secondsplit sense electrode 724 can appear to other circuit components (suchas single-ended sense amplifiers 726 and 728) as signals representativeof the capacitance or change in capacitance with the common mode noiseeliminated or reduced. In some examples, common mode amplifier 730 canimprove common mode rejection (e.g., elimination or mitigation) comparedto using the differential subtraction of common mode noise output bysingle-ended amplifiers 726 and 728. In some examples, common modeamplifier 730 can improve the dynamic range of the single-ended senseamplifiers 722 and 724 due to eliminating or reducing the common modenoise component before the single-ended sense amplifiers amplify thesignals from the touch electrodes.

In some examples, single-ended sense amplifier 726 (e.g., the invertinginput) can be coupled to a first split sense electrode 722 (e.g., senseelectrode 602) and single-ended sense amplifier 728 (e.g., the invertinginput) can be coupled to a second split sense electrode 724 (e.g., senseelectrode 604). The non-inverting inputs of single-ended senseamplifiers 726 and 728 can be coupled to a DC bias voltage. Single-endedsense amplifiers 726 and 728 can have feedback networks, coupled betweenthe output of the sense amplifiers and the inverting input of the senseamplifiers (e.g., similarly to feedback networks 712 and 714). In someexamples, the feedback networks can control the gain of single-endedsense amplifiers 726 and 728. In some examples the feedback networks andcan each include a resistor and/or a capacitor (e.g., with a variableresistance and/or variable capacitance) in parallel or otherwise. Thus,in some examples, the feedback networks can have variable impedances.Thus, because first split sense electrode 722 and second split senseelectrode 724 can have the common mode noise component eliminated orreduced (e.g., by common mode amplifier 730), the output of single-endedsense amplifiers 726 and 728 can be a signal representative of thecapacitance or change in capacitance with the common mode noiseeliminated or reduced. In some examples, the output of single-endedsense amplifiers 726 and 728 can be coupled to a differentialanalog-to-digital converter (ADC) 738. In some examples, the output ofsingle-ended sense amplifier 728 can be inverted by inverter 736 beforecoupling to differential ADC 738 to handle the single-ended todifferential conversion for differential ADC 738. In some examples, theinputs to differential ADC 738 can be non-inverting inputs. In someexamples, inverter 736 can be a noninverting buffer and the input ofdifferential ADC 738 to which inverter 736 is coupled can be aninverting input. In some examples, differential ADC 738 can furtherremove (e.g., eliminate or reduce) any remaining common mode noise,including common mode noise not fully removed by common mode amplifier730 and common mode noise coupled onto the sense signals by othersources or by the components of sense circuit 720. Thus, in someexamples, the output of ADC 738 can be a digital signal representativeof the capacitance or change in capacitance with the common mode noiseeliminated or reduced. In some examples, the resulting signal output byADC 738 can be processed (e.g., decoded, etc.) to detect touch and/orproximity input. In some examples, the resulting signal can be coupledto a processor (e.g., touch processors 202, touch controller 206 and/orhost processor 228.

It is understood that sense circuit 720 can be implemented in any ofsense circuits 626, 656, 686, and 698 described above with respect toFIGS. 6A-6D. For example, in the exemplary method of stimulating andsensing the drive and sense electrodes described in FIG. 6A, sensecircuit 720 can operate as described during the first phase of a mutualcapacitance scan. In such examples, the output of ADC 738 can be adigital signal representative of the capacitance or change incapacitance of the sense electrode of the first bank. During the secondphase of a mutual capacitance scan, the inputs to single-ended senseamplifier 706 and 708 and common mode amplifier 730 can be reversed(e.g., via switching circuitry, such as a multiplexer, not shown). Forexample, single-ended amplifier 726 can be switched to be coupled tosecond split sense electrode 724 (e.g., corresponding to sense electrode604), single-ended amplifier 728 can be switched to be coupled to firstsplit sense electrode 722 (e.g., corresponding to sense electrode 602),the inverting input of common mode amplifier 730 can be switched to becoupled to second split sense electrode 724, and the noninverting inputof common mode amplifier 730 can be switched to be coupled to firstsplit sense electrode 722. Thus, the output of ADC 738 can be a digitalsignal representative of the capacitance or change in capacitance of thesense electrode of the second bank. In some examples, instead ofreversing the inputs to single-ended sense amplifiers 726 and 728 andcommon mode amplifier 730, the inputs of ADC 738 can be reversed toachieve the same effect. In some examples rather than changing thecouplings of the circuit, the polarity of the digital output ofdifferential ADC 738 can be reversed (e.g., the output of ADC 738 can besigned and reversing the polarity can comprise inverting the sign bit ofADC 738).

FIG. 7C illustrates an example sense circuit 740 including fullydifferential sense amplifier 746 and common mode amplifier 750 accordingto examples of the disclosure. In some examples, common mode amplifier750 can be an amplifier with two noninverting inputs, one invertinginput, and two inverting outputs. In some examples, the inverting inputof common mode amplifier 750 can be coupled to a common mode DC biasvoltage 752. In some examples, common mode amplifier 750 can be coupledto a first split sense electrode 742 (e.g., sense electrode 602) at afirst noninverting input and a second split sense electrode 744 (e.g.,sense electrode 604) at a second noninverting input. In some examples,the two inverting outputs of common mode amplifier 750 can be coupled tothe noninverting inputs and act as a feedback loop to common modeamplifier 750. In some examples, in response to the inputs on thenoninverting input, common mode amplifier 750 can output current on theinverting outputs that have an equal (or similar) but opposite magnitudeas the common mode noise component on the noninverting inputs. Thus, insome examples, the outputs of common mode amplifier 750, coupled tofirst split sense electrode 742 and second split sense electrode 744(e.g., as a feedback mechanism), can remove, eliminate, or reduce thecommon mode noise from first split sense electrode 742 and second splitsense electrode 744. Thus, first split sense electrode 742 and secondsplit sense electrode 744 can appear to other circuit components (suchas differential sense amplifier 746) as signals representative of thecapacitance or change in capacitance with the common mode noiseeliminated or reduced. In some examples, common mode amplifier 750 canimprove common mode rejection (e.g., elimination or mitigation) ascompared to using differential subtraction by differential senseamplifier 746 to eliminate or mitigate the common mode noise. In someexamples, common mode amplifier 750 can improve the dynamic range of thedifferential sense amplifier 746 due to eliminating or reducing thecommon mode noise component before differential sense amplifier 746amplifies the signals from the touch electrodes.

In some examples, fully differential sense amplifier 746 can be coupledto first split sense electrode 742 (e.g., sense electrode 602) at theinverting input and to second split sense electrode 744 (e.g., senseelectrode 604) at the non-inverting input. Fully differential senseamplifier 746 can have a feedback network coupled between the output ofdifferential sense amplifiers 746 and the inverting input of fullydifferential sense amplifier 746 and a feedback network coupled betweenthe output of fully differential sense amplifier 746 and thenoninverting input of fully differential sense amplifier 746. In someexamples, the feedback network can control the gain of fullydifferential sense amplifier 746. In some examples the feedback networkcan each include a resistor and/or a capacitor (e.g., with a variableresistance and/or variable capacitance) in parallel or otherwise. Thus,in some examples, the feedback networks can have variable impedances.Thus, because first split sense electrode 742 and second split senseelectrode 744 can have the common mode noise component eliminated orreduced (e.g., by common mode amplifier 750), the output of differentialsense amplifier 746 can be a signal representative of the capacitance orchange in capacitance with the common mode noise eliminated or reduced.In some examples, the output of fully differential sense amplifier 746can be a differential output coupled to a differential analog-to-digitalconverter (ADC) 758. In some examples, differential ADC 758 can furtherremove (e.g., eliminate or reduce) any remaining common mode noise,including common mode noise not fully removed by common mode amplifier750 and common mode noise coupled onto the sense signals by othersources or by the components of sense circuit 740. Thus, in someexamples, the output of ADC 758 can be a digital signal representativeof the capacitance or change in capacitance with the common mode noiseeliminated or reduced. In some examples, the resulting signal output byADC 758 can be processed (e.g., decoded, etc.) to detect touch and/orproximity input. In some examples, the resulting signal can be coupledto a processor (e.g., touch processors 202, touch controller 206 and/orhost processor 228.

It is understood that sense circuit 740 can be implemented in any ofsense circuits 626, 656, 686, and 698 described above with respect toFIGS. 6A-6D. For example, in the exemplary method of stimulating andsensing the drive and sense electrodes described in FIG. 6A, sensecircuit 740 can operate as described during the first phase of a mutualcapacitance scan. In such examples, the output of ADC 758 can be adigital signal representative of the capacitance or change incapacitance of the sense electrode of the first bank. During the secondphase of a mutual capacitance scan, the inputs to differential senseamplifier 746 and common mode amplifier 750 can be reversed (e.g., viaswitching circuitry, such as a multiplexer, not shown). For example, theinverting input of differential amplifier 746 can be switched to becoupled to second split sense electrode 744 (e.g., corresponding tosense electrode 604), the noninverting input of differential amplifier746 can be switched to be coupled to first split sense electrode 742(e.g., corresponding to sense electrode 602), the inverting input ofcommon mode amplifier 750 can be switched to be coupled to second splitsense electrode 744, and the noninverting input of common mode amplifier750 can be switched to be coupled to first split sense electrode 742.Thus, the output of ADC 758 can be a digital signal representative ofthe capacitance or change in capacitance of the sense electrode of thesecond bank. In some examples, instead of reversing the inputs todifferential sense amplifier 746 and common mode amplifier 750, theinputs of ADC 758 can be reversed to achieve the same effect. In someexamples rather than changing the couplings of the circuit, the polarityof the digital output of differential ADC 758 can be reversed (e.g., theoutput of ADC 718 can be signed and reversing the polarity can compriseinverting the sign bit of ADC 758).

FIG. 7D illustrates an example sense circuit 760 includingdifferential-to-single-ended sense amplifier 766 according to examplesof the disclosure. In some examples, differential-to-single-endedamplifier 766 can be coupled to a first split sense electrode 762 (e.g.,sense electrode 602) at the inverting input and a second split senseelectrode 764 (e.g., sense electrode 604) at the noninverting input.Differential-to-single-ended sense amplifier 766 can have a feedbacknetwork 768 coupled between the output of differential-to-single-endedsense amplifier 766 and the inverting input ofdifferential-to-single-ended sense amplifier 766. In some examples,impedance 770 can be coupled to the noninverting input ofdifferential-to-single-ended sense amplifier 766 and be driven by a DCbias voltage 772. In some examples, feedback network 768 can control thegain of differential-to-single-ended sense amplifier 766. In someexamples feedback network 768 and impedance 770 can each include aresistor and/or a capacitor (e.g., with a variable resistance and/orvariable capacitance) in parallel or otherwise. Thus, in some examples,the feedback network 768 and impedance 770 can have variable impedances.In some examples, differential-to-single-ended amplifier 766 cansubtract the signal from the inverting input (e.g., first split senseelectrode 762) from the noninverting input (e.g., second split senseelectrode 764). In such an example, because the signals from thenoninverting input and inverting input both contain the same or similarcommon mode noise component, subtracting the two signals can result in asignal with no or a reduced amount of common mode noise. In someexamples, the output of differential-to-single-ended sense amplifier 766can be a single-ended output coupled to a differential analog-to-digitalconverter (ADC) 778. In some examples, the single-ended output ofdifferential-to-single-ended sense amplifier 766 can be inverted byinverter 776 before coupling to differential ADC 778 to handle thesingle-ended to differential conversion for subtraction (and to amplifythe signal). In some examples, the inputs to differential ADC 778 can benon-inverting inputs. In some examples, inverter 776 can be anoninverting buffer and the input of differential ADC 778 to whichinverter 776 is coupled can be an inverting input. In some examples,differential ADC 778 can further remove (e.g., eliminate or reduce) anyremaining common mode noise, including common mode noise not fullyremoved by differential sense amplifier 766 and common mode noisecoupled onto the sense signals by other sources or by the components ofsense circuit 760. Thus, in some examples, the output of ADC 778 can bea digital signal representative of the capacitance or change incapacitance with the common mode noise eliminated or reduced. In someexamples, the resulting signal output by ADC 778 can be processed (e.g.,decoded, etc.) to detect touch and/or proximity input. In some examples,the resulting signal can be coupled to a processor (e.g., touchprocessors 202, touch controller 206 and/or host processor 228. Althougha differential amplifier 766 is illustrated with a single-ended output,in some examples, differential amplifier 766 can have a differentialoutput that can be coupled to differential ADC 778.

It is understood that sense circuit 760 can be implemented in any ofsense circuits 626, 656, 686, and 698 described above with respect toFIGS. 6A-6D. For example, in the exemplary method of stimulating andsensing the drive and sense electrodes described in FIG. 6A, sensecircuit 760 can operate as described during the first phase of a mutualcapacitance scan. In such examples, the output of ADC 778 can be adigital signal representative of the capacitance or change incapacitance of the sense electrode of the first bank. During the secondphase of a mutual capacitance scan, the inputs to differential senseamplifier 746 can be reversed (e.g., via switching circuitry, such as amultiplexer, not shown). For example, the inverting input ofdifferential amplifier 766 can be switched to be coupled to second splitsense electrode 764 (e.g., corresponding to sense electrode 604) and thenoninverting input of differential amplifier 766 can be switched to becoupled to first split sense electrode 762 (e.g., corresponding to senseelectrode 602). Thus, the output of ADC 778 can be a digital signalrepresentative of the capacitance or change in capacitance of the senseelectrode of the second bank. In some examples, instead of reversing theinputs to differential sense amplifier 766, the inputs of ADC 778 can bereversed to achieve the same effect. In some examples rather thanchanging the couplings of the circuit, the polarity of the digitaloutput of differential ADC 778 can be reversed (e.g., the output of ADC778 can be signed and reversing the polarity can comprise inverting thesign bit of ADC 778).

As described herein, in some examples, the touch controller 206 can beconfigured for different types of sensing scans. For example, asillustrated in FIG. 5, the touch sensor panel can be configured forrow-column mutual capacitance scans by coupling each sense line to asense amplifier of a corresponding sense channel. In some examples, thesense amplifiers can be configured for use in differential mutualcapacitance scans. For example, the sense electrode can be split andeach split sense electrode can be coupled to a sense amplifier of acorresponding sense channel. In some examples, the sense amplifier fromtwo channels can be configured to perform the differential measurement.In such examples, the differential measurements can be performed usingsingle-ended sense amplifiers without requiring dedicated differentialamplifiers for differential sensing measurements.

FIG. 7E illustrates an exemplary configurable sense channel 780according to examples of the disclosure. Sense channel 780 can includesense amplifier 787. In some examples, sense amplifier 787 can include afeedback network coupled between the output of sense amplifier 787 andthe inverting input of sense amplifier 787 to control the gain of senseamplifier 787. Sense amplifier can be used for single-ended ordifferential mutual capacitance sensing and for single-endedself-capacitance sensing. The inverting input of sense amplifier 787 canbe coupled to multiplexer 785 and the noninverting input of senseamplifier 787 can be coupled to multiplexer 786. In some examples,multiplexer 785 can selectively couple node 782 (e.g., a row electrode,or split row electrode) or node 781 (e.g., a column electrode or splitcolumn electrode) to the inverting input of sense amplifier 787. Forexample, in a single-ended mutual capacitance scan or a single-endedself-capacitance scan one sense electrode can be coupled to thenon-inverting input of sense amplifier 787. Multiplexer 786 canselectively couple node 783 (DC bias voltage) or node 784 (Vstim_SC) tothe noninverting input of sense amplifier 787. For a mutual capacitancescan, node 783 can form a virtual ground node for mutual capacitancesensing. For a self-capacitance scan, node 784 can apply aself-capacitance stimulus to stimulate the sense electrode coupled tothe inverting input of sense amplifier 787. In the single-endedconfigurations, the output of sense amplifier 787 can be coupled an ADC791. In some examples, ADC 791 can be a differential ADC and the outputof sense amplifier 787 can be inverted by inverter 790 and coupled toADC 791 (e.g., via multiplexer 789).

In some examples, sense channel 780 can be configured for differentialmutual capacitance measurements. In particular, two of sense channels780 can be used together to form the differential measurement circuitillustrated in FIG. 7B. In the differential mutual capacitance scanconfiguration, sense amplifier 787 can be configured as above for asingle-ended mutual capacitance scan. Namely, multiplexer 785 can coupleone split sense electrode (e.g., in the configuration of FIG. 6A) or onesense electrode (e.g., in the configuration of FIGS. 6B-6C) to thenon-inverting input, and provide a DC bias/virtual ground for thenon-inverting input via multiplexer 786. This sense amplifierconfiguration can correspond to the configuration of sense amplifier 726in FIG. 7B. Sense channel 780 can also be configured to couple with asecond sense channel (not shown) with similar or the same circuitry. Forexample, a second sense channel can include a sense amplifier and can beconfigured in a similar manner as sense amplifier 728 in theconfiguration of FIG. 7B (e.g., by coupling the split or non-split senseelectrode to the inverting input, DC biasing the non-inverting input asa virtual ground). The output of the sense amplifier of the second sensechannel can be coupled to node 793 of sense channel 780 (e.g., from thenode corresponding to 795 of the second sense channel). In thedifferential mutual capacitance scan, multiplexer 789 can couple theoutput of the second sense channel to inverter 790. Thus, ADC 791 canperform a differential measurement on the outputs of two single-endedamplifiers in a similar manner as described herein for FIGS. 7A and 7B.

In some examples, configurable sense channel 780 can include a commonmode amplifier 788. In some examples, common mode amplifier 788 can bean amplifier with two noninverting inputs, one inverting input, and twoinverting outputs. In some examples, the inverting input of common modeamplifier 788 can be coupled to a common mode DC bias voltage (notshown). A first noninverting input of common mode amplifier 788 can becoupled to the inverting input of sense amplifier 787. A secondnoninverting input of common mode amplifier 788 can be coupled to thenon-inverting input of the sense amplifier of the second sense channelvia node 792 of sense channel 780 (e.g., from the node corresponding to794 of the second sense channel). In some examples, the two invertingoutputs of common mode amplifier 788 can be coupled to the noninvertinginputs and act as a feedback loop to common mode amplifier 788 asdescribed above. In some examples, some sense channels can include thecommon mode amplifier 788 and other sense channels can omit common modeamplifier 788 because only one common mode amplifier may be required fortwo sense amplifiers for a differential measurement. Reducing the numberof common mode amplifiers in the touch controller can reduce powerconsumption of the device.

FIG. 8 illustrates an exemplary process 800 to eliminate or reducecommon mode noise according to examples of the disclosure. Process 800can correspond to the configuration of FIG. 6A. At 802, a first phase ofa mutual capacitance scan can be performed. In some examples, the firstphase of the mutual capacitance scan can include one or more of 804,806, 808 and 810. At 804, a first plurality of drive electrodes can bedriven (e.g., driven in a first set of steps). As explained above withrespect to FIG. 6A, in some examples, the first plurality of driveelectrodes can be a first group of split drive electrodes (e.g., fromfirst bank 628, 658). In some examples, while the first plurality ofdrive electrodes is driven, a second plurality of drive electrodes canbe kept at a DC potential (e.g., grounded, driven with a DC signal, orotherwise undriven). At 806, one of more first signals can be sensedfrom one or more first sense electrodes. In some examples, the firstsense electrodes can be sense electrodes from a first bank (e.g., 628,658). In some examples, the one or more first signals can include atouch signal indicative of an object touching or proximate (within athreshold distance) of the touch screen and can include common modenoise injected by a display data line (or other noise sources) andcoupled onto sense electrode. At 808, one or more second signals can besensed from one or more second sense electrodes. In some examples, thesecond sense electrodes can be sense electrodes from a second bank(e.g., 629, 659). In some examples, the one or more second signals caninclude common mode noise injected by the display data line (or othernoise sources) and coupled onto the sense electrodes. In some examples,the common mode noise sensed on the one or more second signals is thesame or similar to the common mode noise sensed on the one or more firstsignals. In some examples, the one or more second signals does notinclude a tough signal (e.g., because drive electrodes of the secondbank are undriven). In some examples, 804 and 806 can be performedconcurrently. In some examples, 806 can be performed before 808. In someexamples, 808 can be performed before 806. At 810, common mode noise canbe filtered from the one or more first signals based on the one or moresecond signals. In some examples, filtering common mode noise caninvolve subtracting the one or more second signals from the one or morefirst signals (e.g., by summing circuit 710). In some examples,filtering common mode noise can involve removing or eliminating thecommon mode noise using a common mode amplifier (such as common modeamplifier 730 and 750). In some examples, filtering common mode noisecan involve removing or eliminating the common mode noise using adifferential amplifier (such as differential amplifier 766) or adifferential ADC (such as ADC 738, 758, 778).

At 812, a second phase of a mutual capacitance scan can be performed. Insome examples, the second phase of the mutual capacitance scan caninclude one or more of 814, 816, 818 and 820. At 814, a second pluralityof drive electrodes can be driven (e.g., driven in a second set ofsteps). As explained above with respect to FIG. 6A, in some examples,the second plurality of drive electrodes can be a second group of splitdrive electrodes (e.g., from second bank 629, 659). In some examples,while the second plurality of drive electrodes is driven, a firstplurality of drive electrodes can be kept at a DC potential (e.g.,grounded, driven with a DC signal, or otherwise undriven). At 816, oneof more third signals can be sensed from one or more second senseelectrodes. In some examples, the second sense electrodes can be senseelectrodes from a second bank (e.g., 629, 659). In some examples, theone or more third signals can include a touch signal indicative of anobject touching or proximate (within a threshold distance) of the touchscreen and can include common mode noise injected by a display data line(or other noise sources) and coupled onto sense electrode. At 818, oneor more fourth signals can be sensed from one or more first senseelectrodes. In some examples, the first sense electrodes can be senseelectrodes from a first bank (e.g., 628, 658). In some examples, the oneor more fourth signals can include common mode noise injected by thedisplay data line (or other noise sources) and coupled onto the senseelectrodes. In some examples, the common mode noise sensed on the one ormore fourth signals is the same or similar to the common mode noisesensed on the one or more third signals. In some examples, the one ormore fourth signals does not include a tough signal (e.g., because driveelectrodes of the first bank are undriven). In some examples, 814 and816 can be performed concurrently. In some examples, 816 can beperformed before 818. In some examples, 818 can be performed before 816.At 820, common mode noise can be filtered from the one or more thirdsignals based on the one or more fourth signals. In some examples,filtering common mode noise can involve subtracting the one or morefourth signals from the one or more third signals (e.g., by summingcircuit 710). In some examples, filtering common mode noise can involveremoving or eliminating the common mode noise using a common modeamplifier (such as common mode amplifier 730 and 750). In some examples,filtering common mode noise can involve removing or eliminating thecommon mode noise using a differential amplifier (such as differentialamplifier 766) or a differential ADC (such as ADC 738, 758, 778).

Although the disclosed examples have been fully described with referenceto mutual capacitance based touch sensor panels (e.g., row-column orpixelated), it is to be understood that common mode noise correctiontechniques described herein can be applied to other touch sensor panelsincluding other types of capacitive based touch sensor panels (e.g.,self-capacitance based), resistive touch sensor panels, or the like. Itis apparent to those skilled in the art that for different sensingtechnologies, modifications would be made to accommodate the sensingtechnology. For example, for a resistive touch sensor panel, the sensornodes can be implemented with resistive sensors and the reference nodescan be implemented with resistive references sensors.

Therefore, according to the above, some examples of the disclosure aredirected to a device. In some examples, the device can comprise drivecircuitry configured to stimulate drive electrodes of a touch sensorpanel; sense circuitry configured to receive sense signals from senseelectrodes of the touch sensor panel; and logic circuitry coupled to thedrive circuitry and the sense circuitry, configured to: during a firstphase of a mutual capacitance scan of the touch sensor panel:simultaneously driving a first plurality of drive electrodes; sensingone or more first sense signals from one or more first sense electrodes,wherein the one or more first sense signals includes a first touchsignal and a first common mode noise signal; sensing one or more secondsense signals from one or more second sense electrodes, wherein the oneor more second sense signals includes a second common mode noise signal;and filtering the first common mode noise from the one or more firstsense signals based on the second common mode noise signal from the oneor more second sense signals; and during a second phase of the mutualcapacitance scan of the touch sensor panel: simultaneously driving asecond plurality of drive electrodes, different from the first pluralityof drive electrodes; sensing one or more third sense signals from theone or more second sense electrodes, wherein the one or more third sensesignals includes a second touch signal and a third common mode noisesignal; sensing one or more fourth sense signals from the one or morefirst sense electrodes, wherein the one or more fourth sense signalsincludes a fourth common mode noise signal; and filtering a third commonmode noise from the one or more third sense signals based on the commonmode noise signal from the one or more fourth sense signals.

Additionally or alternatively, in some examples, the drive circuitry,sense circuitry, and/or logic circuitry is programmed to perform therespective steps described above. Additionally or alternatively, in someexamples, the drive circuitry, sense circuitry, and/or logic circuitryis capable of performing the respective steps described above.

Additionally or alternatively, in some examples, at least one of the oneor more first sense electrodes and at least one of the one or moresecond sense electrodes can be arranged in a column. Additionally oralternatively, in some examples, the one or more first sense signals andthe one or more second sense signals can be concurrently sensed; and theone or more third sense signals and the one or more fourth sense signalscan be concurrently sensed. Additionally or alternatively, in someexamples, the device can further comprise a first display driveelectrode, disposed beneath the one or more first sense electrodes andthe one or more second sense electrodes, configured to provide data to adisplay. Additionally or alternatively, in some examples, the sensecircuitry can comprise: a first single-ended amplifier coupled to one ofthe one or more first sense electrodes; a second single-ended amplifiercoupled to one of the one or more second sense electrodes; and a summingcircuit configured to subtract an output of the second single-endedamplifier from an output of the first single-ended amplifier.Additionally or alternatively, in some examples, the sense circuitry cancomprise: a first single-ended amplifier coupled to one of the one ormore first sense electrodes; a second single-ended amplifier coupled toone of the one or more second sense electrodes; a common mode amplifier,coupled to the one of the one or more first sense electrodes and one ofthe one or more second sense electrodes, configured to filter commonmode noise; and an analog-to-digital converter (ADC).

Additionally or alternatively, in some examples, the sense circuitry cancomprise: a first differential amplifier coupled to one of the one ormore first sense electrodes and one of the one or more second senseelectrodes; a common mode amplifier, coupled to the one of the one ormore first sense electrodes and one of the one or more second senseelectrodes, configured to filter common mode noise; and ananalog-to-digital converter (ADC). Additionally or alternatively, insome examples, the sense circuitry can comprise: a first differentialamplifier coupled to one of the one or more first sense electrodes andone of the one or more second sense electrodes; and an analog-to-digitalconverter (ADC). Additionally or alternatively, in some examples, thesense circuitry can comprise a plurality of sense channels, including afirst sense channel and a second sense channel, and the sense circuitrycan be capable of: during a first sense mode: perform a differentialmeasurement using the first sense channel and the second sense channel;and during a second sense mode: perform a first single-ended measurementusing the first sense channel; and perform a second single-endedmeasurement using the second sense channel.

Some examples of the disclosure are directed a device. In some examples,the device can comprise: drive circuitry configured to stimulate driveelectrodes of a touch screen; sense circuitry configured to receivesense signals from sense electrodes of the touch screen; and logiccircuitry coupled to the drive circuitry and the sense circuitry,configured to: during a mutual capacitance scan of the touch sensorpanel: simultaneously driving a first plurality of drive electrodes anda second plurality of drive electrodes; sensing one or more first sensesignals from one or more first sense electrodes, wherein the one or morefirst sense signals includes a first touch signal and a first commonmode noise signal; sensing one or more second sense signals from one ormore second sense electrodes, wherein the one or more second sensesignals includes a second touch signal and a second common mode noisesignal; filtering the first common mode noise from the one or more firstsense signals based on the second common mode noise signal from the oneor more second sense signals; and filtering the second common mode noisefrom the one or more second sense signals based on the common mode noisesignal from the one or more first sense signals.

Additionally or alternatively, in some examples, the drive circuitry,sense circuitry, and/or logic circuitry is programmed to perform therespective steps described above. Additionally or alternatively, in someexamples, the drive circuitry, sense circuitry, and/or logic circuitryis capable of performing the respective steps described above.

Additionally or alternatively, in some examples, the one or more firstsense electrodes can be arranged in a first row; and the one or moresecond electrodes can be arranged in a second row. Additionally oralternatively, in some examples, the first row and the second row can beadjacent rows. Additionally or alternatively, in some examples, thefirst row and the second row are disposed a threshold distance apart.Additionally or alternatively, in some examples, at least one of thefirst plurality of drive electrodes and at least one of the secondplurality of drive electrodes can be arranged in a column. Additionallyor alternatively, in some examples, the first and second pluralities ofdrive electrodes can be interleaved along the column. Additionally oralternatively, in some examples, the one or more first sense signals andthe one or more second sense signals can be concurrently sensed; and theone or more third sense signals and the one or more fourth sense signalscan be concurrently sensed. Additionally or alternatively, the devicecan further comprise a first display drive electrode, disposed beneaththe first and second pluralities of drive electrodes, configured toprovide data to a display.

Additionally or alternatively, in some examples, the sense circuitry cancomprise: a first single-ended amplifier coupled to one of the one ormore first sense electrodes; a second single-ended amplifier coupled toone of the one or more second sense electrodes; and a summing circuitconfigured to subtract an output of the second single-ended amplifierfrom an output of the first single-ended amplifier. Additionally oralternatively, in some examples, the sense circuitry can comprise: afirst single-ended amplifier coupled to one of the one or more firstsense electrodes, a second single-ended amplifier coupled to one of theone or more second sense electrodes; a common mode amplifier, coupled tothe one of the one or more first sense electrodes and the one of the oneor more second sense electrodes, configured to filter common mode noise;and an analog-to-digital converter (ADC). Additionally or alternatively,in some examples, the sense circuitry can comprise: a first differentialamplifier coupled to one of the one or more first sense electrodes andone of the one or more second sense electrodes; a common mode amplifier,coupled to the one of the one or more first sense electrodes and the oneof the one or more second sense electrodes, configured to filter commonmode noise; and an analog-to-digital converter (ADC).

Additionally or alternatively, in some examples, the sense circuitry cancomprise: a first differential amplifier coupled to one of the one ormore first sense electrodes and one of the one or more second senseelectrodes; and an analog-to-digital converter (ADC). Additionally oralternatively, in some examples, the sense circuitry can comprise aplurality of sense channels, including a first sense channel and asecond sense channel, wherein the sense circuitry can be capable of:during a first sense mode: perform a differential measurement using thefirst sense channel and the second sense channel; and during a secondsense mode: perform a first single-ended measurement using the firstsense channel; and perform a second single-ended measurement using thesecond sense channel.

Some examples of the disclosure are directed to a method. In someexamples, the method can comprise: during a first phase of a mutualcapacitance scan of a touch sensor panel: simultaneously driving a firstplurality of drive electrodes; sensing one or more first sense signalsfrom one or more first sense electrodes, wherein the one or more firstsense signals includes a first touch signal and a first common modenoise signal; sensing one or more second sense signals from one or moresecond sense electrodes, wherein the one or more second sense signalsincludes a second common mode noise signal; and filtering the firstcommon mode noise from the one or more first sense signals based on thesecond common mode noise signal from the one or more second sensesignals; and during a second phase of the mutual capacitance scan of thetouch sensor panel: simultaneously driving a second plurality of driveelectrodes, different from the first plurality of drive electrodes;sensing one or more third sense signals from the one or more secondsense electrodes, wherein the one or more third sense signals includes asecond touch signal and a third common mode noise signal; sensing one ormore fourth sense signals from the one or more first sense electrodes,wherein the one or more fourth sense signals includes a fourth commonmode noise signal; and filtering a third common mode noise from the oneor more third sense signals based on the common mode noise signal fromthe one or more fourth sense signals.

Additionally or alternatively, in some examples, the one or more firstsense signals and the one or more second sense signals can beconcurrently sensed. Additionally or alternatively, in some examples,the method can further comprise: during a first sense mode: performing adifferential measurement using a first sense channel and a second sensechannel; and during a second sense mode: performing a first single-endedmeasurement using the first sense channel; and performing a secondsingle-ended measurement using the second sense channel.

Some examples of the disclosure are directed to a method. In someexamples, the method can comprise: during a mutual capacitance scan of atouch sensor panel: simultaneously driving a first plurality of driveelectrodes and a second plurality of drive electrodes; sensing one ormore first sense signals from one or more first sense electrodes,wherein the one or more first sense signals includes a first touchsignal and a first common mode noise signal; sensing one or more secondsense signals from one or more second sense electrodes, wherein the oneor more second sense signals includes a second touch signal and a secondcommon mode noise signal; filtering the first common mode noise from theone or more first sense signals based on the second common mode noisesignal from the one or more second sense signals; and filtering thesecond common mode noise from the one or more second sense signals basedon the common mode noise signal from the one or more first sensesignals.

Additionally or alternatively, in some examples, the one or more firstsense signals and the one or more second sense signals can beconcurrently sensed. Additionally or alternatively, in some examples,the method can further comprise: during a first sense mode: performing adifferential measurement using a first sense channel and a second sensechannel; and during a second sense mode: performing a first single-endedmeasurement using the first sense channel; and performing a secondsingle-ended measurement using the second sense channel.

Some examples of the disclosure are directed to a non-transitorycomputer readable storage medium. In some examples, the non-transitorycomputer readable medium can contain instructions that, when executed bya device including one or more processors, can perform a method, themethod comprising: during a first phase of a mutual capacitance scan ofa touch sensor panel: simultaneously driving a first plurality of driveelectrodes; sensing one or more first sense signals from one or morefirst sense electrodes, wherein the one or more first sense signalsincludes a first touch signal and a first common mode noise signal;sensing one or more second sense signals from one or more second senseelectrodes, wherein the one or more second sense signals includes asecond common mode noise signal; and filtering the first common modenoise from the one or more first sense signals based on the secondcommon mode noise signal from the one or more second sense signals; andduring a second phase of the mutual capacitance scan of the touch sensorpanel: simultaneously driving a second plurality of drive electrodes,different from the first plurality of drive electrodes; sensing one ormore third sense signals from the one or more second sense electrodes,wherein the one or more third sense signals includes a second touchsignal and a third common mode noise signal; sensing one or more fourthsense signals from the one or more first sense electrodes, wherein theone or more fourth sense signals includes a fourth common mode noisesignal; and filtering a third common mode noise from the one or morethird sense signals based on the common mode noise signal from the oneor more fourth sense signals.

Additionally or alternatively, in some examples, the one or more firstsense signals and the one or more second sense signals can beconcurrently sensed. Additionally or alternatively, in some examples,the method can further comprise: during a first sense mode: performing adifferential measurement using a first sense channel and a second sensechannel; and during a second sense mode: performing a first single-endedmeasurement using the first sense channel; and performing a secondsingle-ended measurement using the second sense channel.

Some examples of the disclosure are directed to a non-transitorycomputer readable storage medium. In some examples, the non-transitorycomputer readable medium can contain instructions that, when executed bya device including one or more processors, can perform a method, themethod comprising: during a mutual capacitance scan of a touch sensorpanel: simultaneously driving a first plurality of drive electrodes anda second plurality of drive electrodes; sensing one or more first sensesignals from one or more first sense electrodes, wherein the one or morefirst sense signals includes a first touch signal and a first commonmode noise signal; sensing one or more second sense signals from one ormore second sense electrodes, wherein the one or more second sensesignals includes a second touch signal and a second common mode noisesignal; filtering the first common mode noise from the one or more firstsense signals based on the second common mode noise signal from the oneor more second sense signals; and filtering the second common mode noisefrom the one or more second sense signals based on the common mode noisesignal from the one or more first sense signals.

Additionally or alternatively, in some examples, the one or more firstsense signals and the one or more second sense signals can beconcurrently sensed. Additionally or alternatively, in some examples,the method can further comprise: during a first sense mode: performing adifferential measurement using a first sense channel and a second sensechannel; and during a second sense mode: performing a first single-endedmeasurement using the first sense channel; and performing a secondsingle-ended measurement using the second sense channel.

It is understood that any element described above as being “configuredto” perform respective functions or steps or operate in a respectivemanner can, in some examples, be programmed to or be capable ofperforming those respective functions or steps or operate in therespective manner. Similarly, any element described above as being“capable of” performing respective functions or steps or operate in arespective manner can, in some examples, be programmed to or beconfigured to perform those respective functions or steps or operate inthe respective manner. Similarly, any element described above as being“programmed to” perform respective functions or steps or operate in arespective manner can, in some examples, be configured to or be capableof performing those respective functions or steps or operate in therespective manner.

Although the disclosed examples have been fully described with referenceto the accompanying drawings, it is to be noted that various changes andmodifications will become apparent to those skilled in the art. Suchchanges and modifications are to be understood as being included withinthe scope of the disclosed examples as defined by the appended claims.

The invention claimed is:
 1. A device comprising: drive circuitryconfigured to stimulate drive electrodes of a touch sensor panel; sensecircuitry configured to receive sense signals from sense electrodes ofthe touch sensor panel; and logic circuitry coupled to the drivecircuitry and the sense circuitry, configured to of: during a mutualcapacitance scan of the touch sensor panel: simultaneously drive a firstplurality of drive electrodes and a second plurality of driveelectrodes; sense one or more first sense signals from one or more firstsense electrodes, wherein the one or more first sense signals includes afirst touch signal and a first common mode noise signal; sense one ormore second sense signals from one or more second sense electrodes,wherein the one or more second sense signals includes a second touchsignal and a second common mode noise signal; filter the first commonmode noise from the one or more first sense signals based on the secondcommon mode noise signal from the one or more second sense signals; andfilter the second common mode noise from the one or more second sensesignals based on the first common mode noise signal from the one or morefirst sense signals.
 2. The device of claim 1, wherein: the one or morefirst sense electrodes are arranged in a first row; and the one or moresecond sense electrodes are arranged in a second row.
 3. The device ofclaim 2, wherein the first row and the second row are adjacent rows. 4.The device of claim 2, wherein the first row and the second row aredisposed a threshold distance apart.
 5. The device of claim 1, whereinat least one of the first plurality of drive electrodes and at least oneof the second plurality of drive electrodes are arranged in a column. 6.The device of claim 5, wherein the first and second pluralities of driveelectrodes are interleaved along the column.
 7. The device of claim 1,wherein: the one or more first sense signals and the one or more secondsense signals are concurrently sensed.
 8. The device of claim 1, furthercomprising a first display drive electrode, disposed beneath the firstand second pluralities of drive electrodes, configured to provide datato a display.
 9. The device of claim 1, wherein the sense circuitrycomprises: a first single-ended amplifier coupled to one of the one ormore first sense electrodes; a second single-ended amplifier coupled toone of the one or more second sense electrodes; and a summing circuitconfigured to subtract an output of the second single-ended amplifierfrom an output of the first single-ended amplifier.
 10. The device ofclaim 1, wherein the sense circuitry comprises: a first single-endedamplifier coupled to one of the one or more first sense electrodes; asecond single-ended amplifier coupled to one of the one or more secondsense electrodes; a common mode amplifier, coupled to the one of the oneor more first sense electrodes and the one of the one or more secondsense electrodes, configured to filter common mode noise; and ananalog-to-digital converter (ADC).
 11. The device of claim 1, whereinthe sense circuitry comprises: a first differential amplifier coupled toone of the one or more first sense electrodes and one of the one or moresecond sense electrodes; a common mode amplifier, coupled to the one ofthe one or more first sense electrodes and the one of the one or moresecond sense electrodes, configured to filter common mode noise; and ananalog-to-digital converter (ADC).
 12. The device of claim 1, whereinthe sense circuitry comprises: a first differential amplifier coupled toone of the one or more first sense electrodes and one of the one or moresecond sense electrodes; and an analog-to-digital converter (ADC). 13.The device of claim 1, wherein: the sense circuitry comprises aplurality of sense channels, including a first sense channel and asecond sense channel, wherein the sense circuitry is configured to:during a first sense mode: perform a differential measurement using thefirst sense channel and the second sense channel; and during a secondsense mode: perform a first single-ended measurement using the firstsense channel; and perform a second single-ended measurement using thesecond sense channel.
 14. A method comprising: during a mutualcapacitance scan of a touch sensor panel: simultaneously driving a firstplurality of drive electrodes and a second plurality of driveelectrodes; sensing one or more first sense signals from one or morefirst sense electrodes, wherein the one or more first sense signalsincludes a first touch signal and a first common mode noise signal;sensing one or more second sense signals from one or more second senseelectrodes, wherein the one or more second sense signals includes asecond touch signal and a second common mode noise signal; filtering thefirst common mode noise from the one or more first sense signals basedon the second common mode noise signal from the one or more second sensesignals; and filtering the second common mode noise from the one or moresecond sense signals based on the first common mode noise signal fromthe one or more first sense signals.
 15. The method of claim 14, whereinthe one or more first sense signals and the one or more second sensesignals are concurrently sensed.
 16. The method of claim 14, furthercomprising: during a first sense mode: performing a differentialmeasurement using a first sense channel and a second sense channel; andduring a second sense mode: performing a first single-ended measurementusing the first sense channel; and performing a second single-endedmeasurement using the second sense channel.
 17. A non-transitorycomputer readable storage medium, the computer readable mediumcontaining instructions that, when executed by a device including one ormore processors, performs a method comprising: during a mutualcapacitance scan of a touch sensor panel: simultaneously driving a firstplurality of drive electrodes and a second plurality of driveelectrodes; sensing one or more first sense signals from one or morefirst sense electrodes, wherein the one or more first sense signalsincludes a first touch signal and a first common mode noise signal;sensing one or more second sense signals from one or more second senseelectrodes, wherein the one or more second sense signals includes asecond touch signal and a second common mode noise signal; filtering thefirst common mode noise from the one or more first sense signals basedon the second common mode noise signal from the one or more second sensesignals; and filtering the second common mode noise from the one or moresecond sense signals based on the first common mode noise signal fromthe one or more first sense signals.
 18. The non-transitory computerreadable storage medium of claim 17, wherein the one or more first sensesignals and the one or more second sense signals are concurrentlysensed.
 19. The non-transitory computer readable storage medium of claim17, the method further comprising: during a first sense mode: performinga differential measurement using a first sense channel and a secondsense channel; and during a second sense mode: performing a firstsingle-ended measurement using the first sense channel; and performing asecond single-ended measurement using the second sense channel.